Phosphorus forms two distinct chlorides, X and Y. Analysis shows that 3.10\text{ g} of pho… — JAMB UTME

Phosphorus forms two distinct chlorides, X and Y. Analysis shows that $3.10\text{ g}$ of phosphorus combines with $10.65\text{ g}$ of chlorine to form compound X, whereas $3.10\text{ g}$ of phosphorus combines with $17.75\text{ g}$ of chlorine to form compound Y. Which law of chemical combination is illustrated by these experimental data, and what is the simple mass ratio of chlorine reacting with the fixed mass of phosphorus?

Law of Multiple Proportions with a ratio of 3 : 5Answer
B
Law of Definite Proportions with a ratio of 3 : 5
C
Law of Multiple Proportions with a ratio of 2 : 3
D
Law of Conservation of Mass with a ratio of 1 : 2

Answer

Law of Multiple Proportions with a ratio of 3 : 5

The option specifying the Law of Multiple Proportions with a ratio of 3 : 5 is correct because the mass of phosphorus is held constant at

3.10\text{ g}

, while the masses of chlorine in compounds X and Y are

10.65\text{ g}

and

17.75\text{ g}

respectively. Simplifying the ratio

\frac{10.65}{17.75}

yields

\frac{3}{5}

(

3 : 5

). Because two elements form different compounds whose mass ratios reduce to simple integers, the observation demonstrates John Dalton's Law of Multiple Proportions.

Step-by-Step Solution

Identify the fixed mass and variable mass values from the given data.

Fixed mass of phosphorus =

3.10\text{ g}

in both compounds. Mass of chlorine in compound X =

10.65\text{ g}

. Mass of chlorine in compound Y =

17.75\text{ g}

The Law of Multiple Proportions compares the varying masses of one element combining with a constant mass of another.

Calculate the simple whole-number ratio of the masses of chlorine.

\frac{10.65}{17.75} = \frac{3}{5} \implies 3 : 5

Dividing both chlorine masses by their greatest common factor (

3.55

) gives the integer ratio

3 : 5

Determine which law of chemical combination corresponds to this relationship.

Law of Multiple Proportions

When two elements form more than one compound, the masses of one element combining with a fixed mass of the other are in a ratio of small whole numbers.

Key Concept

Law of Multiple Proportions

Question

Answer

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