All practice questions

Question 6741Question →

A manufacturing firm in Kano produces large quantities of textiles but experiences cash flow constraints during production cycles. When a merchant wholesaler places advance bulk orders and makes prompt cash payments to the firm, which primary function is being rendered directly to the producer?

Financing production by releasing capital tied up in accumulated stock

Breaking bulk into smaller quantities tailored to consumer purchasing habits

Extending credit facilities and flexible settlement terms to small-scale retailers

Issuing debit notes to correct undercharges on commercial invoices

Show answer & explanation

Answer: Financing production by releasing capital tied up in accumulated stock

Answer

Financing production by releasing capital tied up in accumulated stock

The correct answer highlights the financial function wholesalers perform for producers. By making large bulk purchases and paying promptly, the wholesaler absorbs inventory holding costs and provides the manufacturer with immediate liquidity, thereby funding ongoing manufacturing operations.

Step-by-Step Solution

1

Identify the recipient of the function described in the scenario.

The recipient is the textile manufacturer experiencing cash flow constraints.

The question specifically asks for the service rendered directly to the producer.

2

Distinguish between wholesaler services to manufacturers versus services to retailers.

Services to manufacturers include financing production, risk-bearing, warehousing bulk stock, and market feedback. Services to retailers include breaking bulk, granting credit, and offering variety.

Wholesaler services are strictly categorized by which party in the distribution channel receives the direct benefit.

3

Select the function matching prompt bulk purchasing and cash payments.

Advance bulk purchases and prompt payments replenish the manufacturer's working capital, effectively financing production.

By purchasing finished inventory immediately, the wholesaler frees up the manufacturer's financial resources so production can continue seamlessly.

Key Concept

Wholesaler Functions to Producers vs Retailers

Question 6742Question →

A uniform horizontal beam $XY$ of length $3.0\text{ m}$ and weight $80\text{ N}$ is hinged at end $X$ to a vertical wall. It is held in horizontal equilibrium by a light cable attached to end $Y$ that makes an angle of $30^\circ$ with the beam. What is the tension in the cable?

40\text{ N}

80\text{ N}

160\text{ N}

240\text{ N}

Show answer & explanation

Answer: $80\text{ N}$

Answer

The tension in the cable is

80\text{ N}

.

Taking moments about the hinge at end

X

, the clockwise moment due to the weight of the beam acting at its midpoint (

1.5\text{ m}

) is

80\text{ N} \times 1.5\text{ m} = 120\text{ N}\cdot\text{m}

. The counterclockwise moment provided by the cable tension

T

at end

Y

(

3.0\text{ m}

) is

T \sin(30^\circ) \times 3.0\text{ m} = 1.5 T\text{ N}\cdot\text{m}

. Setting clockwise moments equal to counterclockwise moments gives

1.5 T = 120

, yielding

T = 80\text{ N}

.

Step-by-Step Solution

1

Identify the center of gravity and calculate the clockwise moment about the hinge at end

X

.

Since the beam is uniform, its weight of

80\text{ N}

acts at its center of gravity, which is at a distance of

1.5\text{ m}

from

X

. Clockwise moment =

80\text{ N} \times 1.5\text{ m} = 120\text{ N}\cdot\text{m}

.

For a uniform body, weight acts precisely at the midpoint.

2

Determine the counterclockwise moment exerted by the cable tension

T

about point

X

.

The perpendicular component of the tension is

T \sin(30^\circ)

. Counterclockwise moment =

T \sin(30^\circ) \times 3.0\text{ m} = 1.5 T\text{ N}\cdot\text{m}

.

Only the component of force perpendicular to the beam produces a moment about the pivot.

3

Apply the principle of moments for rotational equilibrium to solve for

T

.

1.5 T = 120 \implies T = \frac{120}{1.5} = 80\text{ N}

.

For equilibrium, total counterclockwise moments about any pivot must equal total clockwise moments.

Key Concept

Principle of Moments and Rotational Equilibrium

Estimated Time:1m 30s

Question 6743Question →

Read the poetic excerpt below and answer the question that follows:

The city sleeps in twilight's grey embrace,
Where idle promises are bought and sold;
The beggar counts the shadows on his face,
While politicians wrap themselves in gold.

Which of the following best describes the tone of the speaker towards the political leaders?

Indignant and critical

Melancholic and serene

Reverent and laudatory

Nostalgic and lighthearted

Show answer & explanation

Answer: Indignant and critical

Answer

The tone of the speaker towards the political leaders is indignant and critical.

The correct answer is indignant and critical because the speaker uses vivid contrasting imagery—comparing the impoverished beggar counting shadows to politicians wrapping themselves in gold—to condemn political greed and corruption.

Step-by-Step Solution

1

Analyze the diction and imagery in the excerpt

The excerpt contrasts the impoverished beggar counting shadows with politicians who 'wrap themselves in gold' through 'idle promises'.

Tone is determined through the speaker's choice of words and imagery regarding a specific subject.

2

Differentiate between tone and mood

While the overall atmospheric mood of the scene is sombre and gloomy, the speaker's specific attitude toward the politicians is condemnation.

Tone reflects the speaker's attitude toward a subject, whereas mood reflects the atmospheric feeling created for the reader.

3

Select the option that accurately captures the speaker's attitude

'Indignant and critical' accurately captures the speaker's moral condemnation of political greed.

The juxtaposition highlights social injustice, proving an indignant and critical stance.

Key Concept

Distinguishing Speaker Tone from Poetic Mood

Question 6744Question →

Three liquid mixtures, $X$ , $Y$ , and $Z$ , were subjected to laboratory tests to determine their physical properties:

- Mixture $X$ scatters a focused beam of light (Tyndall effect), leaves no residue on ordinary filter paper, but fails to pass through a semi-permeable membrane.
- Mixture $Y$ does not scatter light, leaves no residue on ordinary filter paper, and passes freely through a semi-permeable membrane.
- Mixture $Z$ leaves a visible residue on ordinary filter paper and separates into two distinct layers after standing undisturbed.

Which of the following correctly identifies mixtures $X$ , $Y$ , and $Z$ respectively?

Starch mucilage, aqueous sodium chloride, and muddy water

Aqueous sodium chloride, starch mucilage, and fog

Milk of magnesia, starch mucilage, and aqueous glucose

Starch mucilage, muddy water, and aqueous sodium chloride

Show answer & explanation

Answer: Starch mucilage, aqueous sodium chloride, and muddy water

Answer

Mixture X is starch mucilage (colloid), mixture Y is aqueous sodium chloride (true solution), and mixture Z is muddy water (suspension).

Mixture X exhibits the Tyndall effect and is retained only by semi-permeable membranes, which defines a colloidal system such as starch mucilage. Mixture Y shows no light scattering and passes through semi-permeable membranes, characteristic of a true solution like aqueous sodium chloride. Mixture Z forms a residue on filter paper and settles over time, which defines a suspension such as muddy water.

Step-by-Step Solution

1

Analyze the experimental observations for Mixture X

Light scattering (Tyndall effect) combined with passing through ordinary filter paper but being retained by a semi-permeable membrane uniquely identifies a colloidal system (particle diameter

1\text{ nm}

to

100\text{ nm}

). Starch mucilage is a lyophilic colloidal sol.

Colloidal particles are small enough to pass through the macroscopic pores of filter paper but too large to pass through ultra-fine pores of semi-permeable membranes.

2

Analyze the experimental observations for Mixture Y

Absence of Tyndall effect and the ability to pass through both filter paper and semi-permeable membranes indicates a true solution (particle diameter

< 1\text{ nm}

). Aqueous sodium chloride is a homogeneous true solution.

Solute particles in true solutions exist as individual ions or small molecules that do not scatter light and readily pass through semi-permeable membranes.

3

Analyze the experimental observations for Mixture Z

Retention on ordinary filter paper and settling upon standing identifies a suspension (particle diameter

> 100\text{ nm}

). Muddy water is a classic suspension.

Suspension particles are large and heavy enough to be trapped by standard filter paper and to precipitate out under the influence of gravity.

Key Concept

Classification of mixtures into true solutions, colloidal systems, and suspensions based on particle size, light scattering (Tyndall effect), filtration, membrane permeability, and stability.

Question 6745Question →

Match each basic principle of insurance on the left with its correct legal definition or application on the right.

Click a left item, then click its matching right item

Show answer & explanation

Answer

Utmost Good Faith matches full disclosure of material facts; Insurable Interest matches having a financial stake in the subject matter; Proximate Cause matches the direct dominant cause of loss; Subrogation matches the insurer taking over legal rights to claim against third parties.

Each insurance principle correctly pairs with its legal application: Utmost Good Faith obligates disclosure of material facts, Insurable Interest establishes a legal financial connection to the insured item, Proximate Cause pinpoint the dominant operational origin of damage, and Subrogation substitutes the insurer into the insured's recovery rights against third parties.

Step-by-Step Solution

1

Identify the meaning of Utmost Good Faith

It establishes a duty to disclose all material facts without misrepresentation or concealment.

Insurance contracts rely on mutual trust between the insurer and the insured.

2

Identify the meaning of Insurable Interest

It requires the insured to have a legal and financial stake in the subject matter.

Without insurable interest, an insurance policy constitutes an illegal gambling or wagering contract.

3

Identify the meaning of Proximate Cause

It determines the actual primary cause setting off the chain of events leading to damage.

Insurers only pay for losses caused directly by insured perils.

4

Identify the meaning of Subrogation

It allows an insurer who has fully indemnified the insured to pursue a negligent third party for damages.

It prevents the insured from profiting by recovering compensation twice for a single loss.

Key Concept

Basic Principles of Insurance

Question 6746Question →

Match each mixture listed on the left with its correct classification or colloidal type on the right based on particle size and physical characteristics.

Click a left item, then click its matching right item

Show answer & explanation

Answer

Starch mucilage matches with Sol (solid in liquid colloid); Aqueous sodium chloride solution matches with True solution; Muddy water matches with Suspension; Fog matches with Aerosol (liquid in gas colloid).

Starch mucilage is a colloidal sol because it contains solid macromolecular starch particles (

1\text{--}100\text{ nm}

) dispersed in liquid water. Aqueous sodium chloride is a true solution because its solute is completely dissociated into ions smaller than

1\text{ nm}

. Muddy water is a suspension because its insoluble soil particles are larger than

100\text{ nm}

and settle out under gravity. Fog is an aerosol because it consists of liquid water droplets suspended in gas (air).

Step-by-Step Solution

1

Analyze the particle size, homogeneity, and physical stability of each mixture.

Identify whether the mixture has particles

<1\text{ nm}

(true solution),

1\text{--}100\text{ nm}

(colloid), or

>100\text{ nm}

(suspension).

Particle dimensions dictate light scattering (Tyndall effect), filtration capabilities, and gravity settling.

2

Determine the dispersed phase and dispersion medium for colloidal systems.

Starch in water is solid dispersed in liquid (sol); water droplets in air are liquid dispersed in gas (aerosol).

Colloidal systems are classified based on the physical states of the dispersed phase and the dispersion medium.

3

Match each mixture to its corresponding system classification.

Starch mucilage

\rightarrow

Sol; Aqueous NaCl

\rightarrow

True solution; Muddy water

\rightarrow

Suspension; Fog

\rightarrow

Aerosol.

Verification against physical properties confirms all four correct pairs.

Key Concept

Distinction among true solutions, colloidal dispersions (sols, aerosols, emulsions), and suspensions based on particle size and physical behavior.

Question 6747Question →

A commercial distributor operates as a vital intermediary between industrial manufacturers and retail shops. Arrange the following operational functions of a merchant wholesaler in the correct chronological sequence, from initial bulk procurement down to final delivery to retailers.

Drag items to arrange them in the correct order

Show answer & explanation

Answer

The correct sequence of wholesale operations is: purchasing finished merchandise in bulk from producers, storing stock in central warehouses, sorting and breaking bulk into smaller standardized packages, and finally selling smaller lots to retail shops on credit terms.

The operational flow of wholesale trade begins with bulk purchasing directly from industrial manufacturers. The inventory is then moved into central warehouses for storage. Inside the warehouse, the wholesaler performs bulk breaking, grading, and repackaging into smaller lots. Finally, these smaller packages are sold and dispatched to retail traders, frequently accompanied by commercial credit facilities.

Step-by-Step Solution

1

Identify the initial supply chain entry point

Purchasing in bulk directly from producers is the starting point of the wholesale trade process.

Wholesalers must first acquire title and possession of manufactured goods before performing internal handling.

2

Determine the immediate post-procurement storage function

Storing stock in central warehousing follows bulk purchasing.

Holding stock buffers against price volatility and ensures continuity of market supply.

3

Identify the primary value-addition processing stage

Sorting, grading, and breaking bulk into smaller packages occurs while goods are held in inventory.

Retailers cannot purchase factory bulk units, so the wholesaler must repackage items into smaller quantities.

4

Establish the final distribution stage to retail outlets

Selling and dispatching smaller lots to retail shops on credit terms completes the wholesale operational sequence.

This places the products into the retail trade channel for ultimate sale to consumers.

Key Concept

Sequential Functions of Merchant Wholesalers in Distribution Channels

Question 6748Question →

Match each separation requirement on the left with the most appropriate physical separation technique on the right.

Click a left item, then click its matching right item

Show answer & explanation

Answer

The correct pairings match chalk suspension with filtration, anhydrous sodium chloride recovery with evaporation to dryness, hydrated iron(II) tetraoxosulfate(VI) recovery with crystallization, and separating multiple soluble salts of varying temperature dependence with fractional crystallization.

Filtration is used for insoluble suspended solids (chalk). Evaporation to dryness is appropriate for thermally stable, non-hydrated solutes (sodium chloride). Crystallization prevents thermal decomposition and preserves water of crystallization in heat-sensitive salts (hydrated iron(II) tetraoxosulfate(VI)). Fractional crystallization separates multiple dissolved salts based on differences in their solubility curves at varying temperatures.

Step-by-Step Solution

1

Examine the solubility of the component to be separated from the liquid medium.

Chalk is insoluble and forms a suspension, whereas sodium chloride, hydrated iron(II) tetraoxosulfate(VI), potassium trioxonitrate(V), and potassium chloride dissolve completely.

Insoluble solids are separated mechanically via filtration, whereas dissolved solutes require thermal or solubility-based techniques.

2

Assess the thermal stability and hydration requirements of single dissolved solutes.

Sodium chloride is thermally stable and recovered as an anhydrous salt, while hydrated iron(II) tetraoxosulfate(VI) (

\text{FeSO}_4\cdot7\text{H}_2\text{O}

) loses its water of crystallization and decomposes under strong heat.

Thermally stable salts can be evaporated to dryness, whereas thermally labile or hydrated salts require gentle concentration followed by cooling (crystallization).

3

Evaluate solutions containing multiple soluble solid solutes.

Potassium trioxonitrate(V) (

\text{KNO}_3

) and potassium chloride (

\text{KCl}

) have distinct solubility curves across temperatures.

Fractional crystallization selectively precipitates the less soluble component at a given temperature while leaving the more soluble component in solution.

Key Concept

Selection criteria for filtration, evaporation to dryness, crystallization, and fractional crystallization based on solute solubility, thermal stability, hydration state, and temperature dependence.

Question 6749Question →

Which form of control is directly exercised over a public corporation when the legislature debates its audited annual financial statements and examines its operational reports?

Parliamentary control

Ministerial control

Judicial control

Public or consumer control

Show answer & explanation

Answer: Parliamentary control

Answer

Parliamentary control

Public corporations are statutory entities created by an Act of Parliament. Consequently, Parliament retains ultimate oversight authority, requiring these corporations to submit annual reports and audited accounts to be presented, debated, and evaluated by legislators.

Step-by-Step Solution

1

Identify the controlling body and mechanism described in the stem.

The body mentioned is the legislature (parliament), and the mechanism is reviewing annual accounts and operational reports.

Public corporations are established by Acts of Parliament, making them accountable to the legislative assembly.

2

Distinguish parliamentary control from executive and legal control mechanisms.

Legislative debate over annual financial statements constitutes parliamentary control.

Ministers handle administrative supervision, courts handle legal/ultra vires issues, and parliament handles ultimate legislative scrutiny.

Key Concept

Parliamentary control of public enterprises

Question 6750Question →

An aqueous solution of a weak monoacidic base, $\text{BOH}$ , has a concentration of $0.20\text{ mol dm}^{-3}$ and a base dissociation constant $K_b = 5.0 \times 10^{-6}\text{ mol dm}^{-3}$ at $25^\circ\text{C}$ . Calculate the pH of this solution.

Show answer & explanation

Answer: 11

Answer

The pH of the weak monoacidic base solution is 11.0.

For a weak base, partial equilibrium ionization gives

[\text{OH}^-] = \sqrt{K_b \times C} = \sqrt{5.0 \times 10^{-6} \times 0.20} = 1.0 \times 10^{-3}\text{ mol dm}^{-3}

. The pOH is

-\log_{10}(1.0 \times 10^{-3}) = 3.0

. Using

\text{pH} = 14.0 - \text{pOH}

, the pH of the basic solution is

14.0 - 3.0 = 11.0

.

Step-by-Step Solution

1

Formulate the dissociation equilibrium equation for the weak base BOH.

The ionization is

\text{BOH}_{(aq)} \rightleftharpoons \text{B}^+_{(aq)} + \text{OH}^-_{(aq)}

, giving

K_b = \frac{[\text{B}^+][\text{OH}^-]}{[\text{BOH}]}

.

Weak bases ionize incompletely in aqueous media.

2

Calculate the equilibrium hydroxide ion concentration [OH⁻].

[\text{OH}^-] = \sqrt{K_b \times C} = \sqrt{(5.0 \times 10^{-6})(0.20)} = 1.0 \times 10^{-3}\text{ mol dm}^{-3}

.

Since the base is weak and degree of ionization is small,

[\text{BOH}] \approx 0.20\text{ mol dm}^{-3}

and

[\text{B}^+] = [\text{OH}^-]

.

3

Determine the pOH of the solution.

\text{pOH} = -\log_{10}(1.0 \times 10^{-3}) = 3.0

.

pOH is defined as

-\log_{10}[\text{OH}^-]

.

4

Calculate the pH using the relationship between pH and pOH at 25°C.

\text{pH} = 14.0 - \text{pOH} = 14.0 - 3.0 = 11.0

.

At

25^\circ\text{C}

,

\text{pH} + \text{pOH} = 14.0

.

Key Concept

Weak base dissociation equilibrium and pH determination

Question 6751Question →

A $500\text{ cm}^3$ sample of air collected near an industrial plant containing nitrogen ( $\text{N}_2$ ), oxygen ( $\text{O}_2$ ), carbon dioxide ( $\text{CO}_2$ ), and sulfur dioxide ( $\text{SO}_2$ ) pollutant was passed through concentrated potassium hydroxide ( $\text{KOH}$ ) solution, reducing the gas volume to $485\text{ cm}^3$ . The residual gas mixture was subsequently passed through excess alkaline solution of pyrogallol, resulting in a final volume of $383\text{ cm}^3$ . What is the percentage by volume of oxygen in the original air sample?

Show answer & explanation

Answer: 20.4

Answer

20.4%

Concentrated potassium hydroxide (KOH) absorbs the acidic gas pollutants (carbon dioxide and sulfur dioxide), causing an initial volume contraction of

15\text{ cm}^3

. Alkaline pyrogallol then absorbs elemental oxygen gas (

\text{O}_2

), causing a further contraction from

485\text{ cm}^3

to

383\text{ cm}^3

, which corresponds to

102\text{ cm}^3

of

\text{O}_2

. Dividing this volume of oxygen by the original total sample volume of

500\text{ cm}^3

and multiplying by

100\%

yields

20.4\%

.

Step-by-Step Solution

1

Identify the volume reduction caused by potassium hydroxide (KOH)

KOH absorbs acidic gases CO₂ and SO₂:

500\text{ cm}^3 - 485\text{ cm}^3 = 15\text{ cm}^3

.

Potassium hydroxide is an alkaline reagent that selectively absorbs acidic oxides present in polluted air.

2

Determine the volume of oxygen gas absorbed by alkaline pyrogallol

Alkaline pyrogallol absorbs O₂:

485\text{ cm}^3 - 383\text{ cm}^3 = 102\text{ cm}^3

.

Alkaline pyrogallol is a specific quantitative reagent used to absorb unreacted oxygen gas.

3

Calculate the percentage volume of oxygen in the initial sample

\left(\frac{102\text{ cm}^3}{500\text{ cm}^3}\right) \times 100\% = 20.4\%

.

The volume percentage of a component in air is the ratio of its volume to the total initial unreacted air sample volume multiplied by 100.

Key Concept

Quantitative volumetric determination of atmospheric components and gaseous pollutants using selective absorbents

Estimated Time:2m 0s

Question 6752Question →

A progressive transverse wave propagating along a taut string is governed by the equation $y = 0.03 \sin(80\pi t - 5\pi x)$ , where $x$ and $y$ are in meters and $t$ is in seconds. What is the phase difference in radians between two points on the string separated by a distance of $0.1\text{ m}$ ?

\frac{\pi}{2}\text{ rad}

\pi\text{ rad}

\frac{\pi}{4}\text{ rad}

8\pi\text{ rad}

Show answer & explanation

Answer: $\frac{\pi}{2}\text{ rad}$

Answer

The phase difference between the two points is

\frac{\pi}{2}\text{ rad}

.

Comparing the given equation

y = 0.03 \sin(80\pi t - 5\pi x)

with the standard form

y = A \sin(\omega t - k x)

shows that

k = 5\pi\text{ rad/m}

. Substituting this wave number and the distance separation

\Delta x = 0.1\text{ m}

into

\Delta \phi = k \Delta x

yields

\Delta \phi = 5\pi \times 0.1 = 0.5\pi\text{ rad}

, which is equal to

\frac{\pi}{2}\text{ rad}

.

Step-by-Step Solution

1

Identify the wave number

k

from the given wave equation.

k = 5\pi\text{ rad/m}

The standard progressive wave equation is

y = A \sin(\omega t - k x)

, where the coefficient of

x

is

k

.

2

Calculate the phase difference

\Delta \phi

for a spatial separation

\Delta x = 0.1\text{ m}

.

\Delta \phi = k \Delta x = 5\pi \times 0.1 = 0.5\pi\text{ rad} = \frac{\pi}{2}\text{ rad}

Phase difference is directly proportional to spatial separation via

\Delta \phi = k \Delta x = \frac{2\pi}{\lambda}\Delta x

.

Key Concept

Phase Difference in Progressive Waves

Question 6753Question →

A

5.00\text{ g}

sample of impure sodium trioxocarbonate(IV),

\text{Na}_2\text{CO}_3

, reacted completely with excess dilute hydrochloric acid to produce

0.896\text{ dm}^3

of carbon(IV) oxide gas at STP according to the equation:

\text{Na}_2\text{CO}_3(s) + 2\text{HCl}(aq) \rightarrow 2\text{NaCl}(aq) + \text{H}_2\text{O}(l) + \text{CO}_2(g)

What is the percentage purity of the sodium trioxocarbonate(IV) sample?

[\text{Molar volume of gas at STP} = 22.4\text{ dm}^3\text{mol}^{-1}, \text{Na} = 23, \text{C} = 12, \text{O} = 16]

84.8%

79.1%

66.4%

42.4%

Show answer & explanation

Answer: 84.8%

Answer

The percentage purity of the sodium trioxocarbonate(IV) sample is 84.8%.

The correct answer of 84.8% is obtained by converting the volume of carbon(IV) oxide gas at STP to moles using the molar volume of 22.4 dm³/mol, determining the equivalent mass of pure sodium trioxocarbonate(IV) using its molar mass (106 g/mol), and finding its proportion relative to the 5.00 g sample mass.

Step-by-Step Solution

1

Calculate the number of moles of carbon(IV) oxide gas produced at STP.

n(\text{CO}_2) = \frac{0.896\text{ dm}^3}{22.4\text{ dm}^3\text{mol}^{-1}} = 0.04\text{ mol}

At STP, one mole of any gas occupies a volume of

22.4\text{ dm}^3

.

2

Determine the molar mass and the mass of pure sodium trioxocarbonate(IV).

Molar mass of

\text{Na}_2\text{CO}_3 = (2 \times 23) + 12 + (3 \times 16) = 106\text{ g/mol}

. Mass of pure

\text{Na}_2\text{CO}_3 = 0.04\text{ mol} \times 106\text{ g/mol} = 4.24\text{ g}

.

From the balanced chemical equation,

1\text{ mol}

of

\text{Na}_2\text{CO}_3

yields

1\text{ mol}

of

\text{CO}_2

.

3

Calculate the percentage purity of the sample.

\text{Percentage Purity} = \left(\frac{\text{Mass of pure } \text{Na}_2\text{CO}_3}{\text{Mass of impure sample}}\right) \times 100\% = \left(\frac{4.24\text{ g}}{5.00\text{ g}}\right) \times 100\% = 84.8\%

.

Percentage purity expresses the mass of the pure reacting component relative to the total sample mass.

Key Concept

Percentage Purity from Gas Stoichiometry

Estimated Time:1m 30s

Question 6754Question →

Match each character from the prescribed African prose texts to their corresponding narrative role or defining experience within their respective novels.

Click a left item, then click its matching right item

Show answer & explanation

Answer

Yaremi matches with resisting oppressive widowhood customs in Kufi; Fofo matches with navigating street life in Accra to find the truth about her sister's death; Major Ali matches with striving to maintain moral integrity as a military commander during the civil war; Esi Sekyi matches with leaving a restrictive monogamous marriage for career and personal autonomy.

Each character is accurately paired with their defining narrative conflict and thematic significance across the prescribed African prose syllabus texts.

Step-by-Step Solution

1

Identify the central conflict and character trajectory for Yaremi in *Lonely Days*.

Yaremi's storyline revolves around her refusal to yield to traditional widow inheritance rites following the death of Ajumobi.

This establishes her match with the description of resisting widowhood customs in Kufi village.

2

Analyze the character arc of Fofo in *Faceless*.

Fofo lives on the streets of Agbogbloshie, Accra, and investigates the tragic fate of her sister Baby T with the help of MNS Agency.

This aligns her directly with the description of surviving Accra street life while uncovering her sister's death.

3

Examine Major Ali's narrative role in *The Last Duty*.

As the commander of the federal troops in Uruk, Major Ali attempts to temper war atrocities and act impartially toward the civilian population.

This confirms his match as the military commander striving for moral integrity during the civil war.

4

Evaluate Esi Sekyi's decisions in *Changes: A Love Story*.

Esi leaves her demanding first husband Ako to seek a relationship structure that permits her professional independence.

This matches her with the description of leaving a monogamous marriage for career self-actualization.

Key Concept

Characterization and thematic roles in prescribed African prose texts

Question 6755Question →

An aqueous solution of ammonium trioxonitrate(V), $NH_4NO_3$ , turns blue litmus paper red. Which species and hydrolysis reaction account for this acidity?

Cation hydrolysis where

NH_4^+

reacts with water to produce

H^+

ions

Anion hydrolysis where

NO_3^-

reacts with water to produce

OH^-

ions

Neutralization between

NH_4^+

and

NO_3^-

ions in solution

Indicator interaction where

NO_3^-

directly alters litmus color without changing pH

Show answer & explanation

Answer: Cation hydrolysis where $NH_4^+$ reacts with water to produce $H^+$ ions

Answer

Cation hydrolysis where

NH_4^+

reacts with water to produce

H^+

ions

The ammonium salt

NH_4NO_3

is formed from a strong acid (

HNO_3

) and a weak base (

NH_3

). Upon dissolving in water, the cation

NH_4^+

reacts with water molecules (cation hydrolysis) according to the equilibrium

NH_4^+ + H_2O ⇌ NH_3 + H^+

. The generation of excess hydrogen ions makes the solution acidic and turns blue litmus red.

Step-by-Step Solution

1

Identify the parent acid and parent base of the salt

NH_4NO_3

is formed from a weak base (

NH_3

) and a strong acid (

HNO_3

).

Salts formed from weak bases and strong acids dissolve in water to produce acidic solutions.

2

Determine which ion undergoes hydrolysis

The ammonium cation (

NH_4^+

) hydrolyzes:

NH_4^+ (aq) + H_2O (l) ⇌ NH_3 (aq) + H^+ (aq)

.

The conjugate acid of a weak base is strong enough to react with water, whereas the conjugate anion of a strong acid (

NO_3^-

) is a spectator ion.

3

Relate ion generation to solution acidity

Production of excess

H^+

ions turns blue litmus paper red.

Increased hydrogen ion concentration lowers pH below 7.

Key Concept

Hydrolysis of salts derived from strong acids and weak bases

Estimated Time:45s

Question 6756Question →

A uniform horizontal plank $AB$ of length $5.0\text{ m}$ and mass $40\text{ kg}$ rests on two smooth supports, $C$ and $D$ , located $1.0\text{ m}$ from end $A$ and $1.0\text{ m}$ from end $B$ respectively. What is the maximum mass, in kilograms, of an object that can be placed at end $A$ without causing the plank to tilt?

Show answer & explanation

Answer: 60

Answer

The maximum mass that can be placed at end A without tilting the plank is 60 kg.

Just before tilting, the plank rotates around support C, causing the normal reaction at support D to drop to zero. Equating the anticlockwise moment of the added mass at end A about support C (

(m \cdot g) \times 1.0\text{ m}

) to the clockwise moment of the plank's weight about support C (

(40 \cdot g) \times 1.5\text{ m}

) yields

m = 60\text{ kg}

.

Step-by-Step Solution

1

Identify the tipping condition and pivot point

Support C acts as the pivot; the reaction at support D becomes zero (

R_D = 0

).

When extra weight is added at end A, the plank rotates about C and lifts off support D.

2

Calculate perpendicular distances from the pivot C

Distance to added mass

m

=

1.0\text{ m}

; Distance to plank's center of mass =

2.5\text{ m} - 1.0\text{ m} = 1.5\text{ m}

.

The weight of a uniform beam acts at its midpoint (2.5 m from either end).

3

Equate clockwise and counterclockwise moments about C

m \times g \times 1.0\text{ m} = 40\text{ kg} \times g \times 1.5\text{ m}

, giving

m = 60\text{ kg}

.

For the plank to remain balanced just before tipping, total anticlockwise moment must equal total clockwise moment.

Key Concept

Rotational Equilibrium and Tilting of Rigid Bodies

Estimated Time:1m 30s

Question 6757Question →

Match each poetic excerpt with the dominant literary element (tone, mood, or persona) it illustrates.

Click a left item, then click its matching right item

Show answer & explanation

Answer

The excerpt regarding iron gears matches the indignant tone; the excerpt about the moonlit stream matches the tranquil mood; and the excerpt starting with 'I am the ancient spirit' matches the non-human poetic persona.

Each pair correctly aligns the poetic text with its primary literary attribute: tone reflects speaker anger toward injustice, mood reflects reader calm through gentle nature imagery, and persona represents a personified nature entity speaking directly.

Step-by-Step Solution

1

Analyze the speaker's attitude in the first excerpt

Identified strong criticism of social inequality, which reflects an indignant tone.

Tone refers specifically to the speaker's emotional attitude toward the subject matter.

2

Examine the emotional atmosphere created in the second excerpt

Identified imagery that evokes serenity and restfulness, establishing a tranquil mood.

Mood refers to the atmosphere created by the text to evoke feelings in the reader.

3

Determine the identity of the speaker in the third excerpt

Identified the speaker as a personified elemental entity ('spirit of the soil').

Persona is the adopted voice or character through which the poem is spoken.

Key Concept

Distinguishing Tone (speaker's attitude), Mood (reader's feeling/atmosphere), and Persona (speaking identity) in Poetry

Question 6758Question →

A wholesaler purchases bulk quantities of detergent from a manufacturing firm in Ogun State and divides the consignment into smaller packages suitable for neighborhood retail shops. Which function is the wholesaler performing directly for the retailers in this situation?

Breaking bulk to suit their purchasing capacity

Financing production by releasing capital ahead of sales

Providing market research feedback regarding consumer demand

Issuing credit notes to rectify overcharged invoices

Show answer & explanation

Answer: Breaking bulk to suit their purchasing capacity

Answer

Breaking bulk to suit their purchasing capacity

Breaking bulk is a primary service rendered by wholesalers to retailers. Manufacturers produce in large quantities to gain economies of scale, while small retailers require small quantities to match limited capital and storage space. The wholesaler bridges this gap by purchasing in bulk and dividing goods into smaller units.

Step-by-Step Solution

1

Analyze the activity described in the scenario.

The wholesaler buys in bulk from the manufacturer and divides large consignments into smaller quantities for retail shops.

Retailers typically operate on smaller capital scales and cannot afford or store huge quantities of goods directly from manufacturers.

2

Distinguish between wholesaler functions provided to manufacturers versus retailers.

Dividing large packs into smaller units (breaking bulk) directly serves retailers, enabling them to stock a variety of items without over-stretching their working capital.

Functions like financing production and transmitting market feedback serve the manufacturer, whereas breaking bulk and providing variety serve the retailer.

Key Concept

Functions of Wholesalers to Retailers

Estimated Time:1m 0s

Question 6759Question →

What volume of hydrogen gas, measured at STP, is produced when $4.8\text{ g}$ of magnesium ribbon reacts completely with excess dilute tetraoxosulfate(VI) acid according to the chemical equation below?

Mg(s) + H_2SO_4(aq) \rightarrow MgSO_4(aq) + H_2(g)

$[Mg = 24, \text{Molar volume of gas at STP} = 22.4\text{ dm}^3\text{mol}^{-1}]$

Show answer & explanation

Answer: 4.48

Answer

The volume of hydrogen gas produced at STP is

4.48\text{ dm}^3

.

From the stoichiometric relationship in the balanced reaction

Mg(s) + H_2SO_4(aq) \rightarrow MgSO_4(aq) + H_2(g)

,

1\text{ mol}

of

Mg

(

24\text{ g}

) produces

1\text{ mol}

of

H_2

gas (

22.4\text{ dm}^3

at STP). For

4.8\text{ g}

of

Mg

, the number of moles is

\frac{4.8}{24} = 0.20\text{ mol}

. Multiplying by the molar gas volume gives

0.20 \times 22.4 = 4.48\text{ dm}^3

of

H_2

gas.

Step-by-Step Solution

1

Calculate the amount in moles of magnesium (

Mg

) reacted.

n(Mg) = \frac{4.8\text{ g}}{24\text{ g mol}^{-1}} = 0.20\text{ mol}

Dividing given mass by relative atomic mass yields the number of moles.

2

Determine the amount in moles of hydrogen gas (

H_2

) produced.

n(H_2) = 0.20\text{ mol}

The balanced chemical equation shows a

1:1

stoichiometric molar ratio between

Mg

and

H_2

.

3

Calculate the volume of

H_2

gas at STP.

V(H_2) = 0.20\text{ mol} \times 22.4\text{ dm}^3\text{mol}^{-1} = 4.48\text{ dm}^3

At standard temperature and pressure (STP), one mole of any gas occupies

22.4\text{ dm}^3

.

Key Concept

Mass-Volume stoichiometric calculation at STP

Question 6760Question →

A logistics company's delivery truck was damaged in a road accident caused entirely by a reckless third-party driver. The insurance company fully indemnified the logistics company for the repair costs of $1,200,000$ Naira and subsequently sued the reckless driver to recover the money paid. Which principle of insurance entitles the insurer to take legal action against the third party in place of the insured?

Subrogation

Contribution

Utmost Good Faith

Insurable Interest

Show answer & explanation

Answer: Subrogation

Answer

Subrogation

Subrogation is the principle of insurance that allows an insurer, after compensating the insured for a loss, to inherit all legal rights and remedies of the insured against a third party who caused the loss.

Step-by-Step Solution

1

Analyze the legal scenario between the insured, the insurer, and the third party.

The insurer indemnified the logistics company and then initiated legal action against the negligent third party responsible for the collision.

Identifying the specific legal right exercised after full claim settlement isolates the controlling insurance principle.

2

Evaluate the definition of subrogation in commercial insurance.

Subrogation transfers the legal rights of recovery from the insured party to the insurer once full compensation has been paid.

This prevents the insured from collecting double compensation (from both the insurer and the negligent driver) and ensures the liable party pays for the damage caused.

Key Concept

Subrogation in Insurance Contracts

Answer

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