Match each electrolytic setup to the primary factor or mechanism governing the electrode r… — JAMB UTME

Match each electrolytic setup to the primary factor or mechanism governing the electrode reaction during electrolysis.

Electrolysis of concentrated $NaCl_{(aq)}$ (brine) using inert platinum electrodes (anode reaction)Preferential discharge of $Cl^-$ to liberate $Cl_2$ gas driven predominantly by high ion concentration
Electrolysis of $CuSO_{4(aq)}$ using copper electrodes (anode reaction)Dissolution of the copper metal anode into $Cu^{2+}$ ions governed by the nature of the active electrode
Electrolysis of dilute $H_2SO_{4(aq)}$ using inert platinum electrodes (anode reaction)Preferential discharge of $OH^-$ to liberate $O_2$ gas determined by position in the electrochemical series
Electrolysis of molten $NaCl_{(l)}$ using inert carbon electrodes (cathode reaction)Direct discharge of $Na^+$ to produce sodium metal due to the absence of competing aqueous ions

Answer

The correct matches pair each electrolytic process with its underlying discharge factor: concentrated brine anode discharge is governed by ion concentration; active copper anode reaction is governed by electrode nature; dilute acid anode discharge depends on electrochemical series position; and molten salt electrolysis operates in the absence of competing ions.

Each electrolytic scenario is correctly matched to the principal factor governing its reaction: concentrated aqueous

NaCl

anode output is determined by ion concentration; copper electrode electrolysis depends on active electrode participation; dilute

H_2SO_4

anode output is dictated by relative positions in the electrochemical series; and molten

NaCl

involves discharge without competing aqueous ions.

Step-by-Step Solution

Examine the electrolysis of concentrated

NaCl_{(aq)}

at the anode

High concentration of

Cl^-

overrides the electrochemical series position of

OH^-

Concentration factor dominates when halide ion concentration is high.

Examine the electrolysis of

CuSO_{4(aq)}

with copper electrodes

The copper anode dissolves into

Cu^{2+}

ions.

An active electrode participates chemically in the reaction instead of inert anion discharge.

Examine the electrolysis of dilute

H_2SO_{4(aq)}

with inert electrodes

OH^-

is discharged in preference to

SO_4^{2-}

to give oxygen gas.

OH^-

is positioned higher in the electrochemical series than

SO_4^{2-}

Examine the electrolysis of molten

NaCl_{(l)}

Na^+

ions are discharged at the cathode.

Without water, there are no competing

H^+

ions present.

Key Concept

Factors governing the preferential discharge of ions during electrolysis (concentration of ions, nature of electrodes, and position in the electrochemical series)

Question

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

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