Question

$Cu^{2 +}$ ions reacts with $Fe^{2 +}$ ion according to the following reaction

$Cu^{2 +}+2Fe^{2 +}\rightleftharpoons Cu+2Fe^{3 +}$

At equilibrium the concentration of $Cu^{2 +}$ ions is not changed by the addition of

• A. $Cu^{2 +}$
• B. $Fe^{2 +}$
• C. Cu
• D. $Fe^{3 +}$

Answer 1

Answer: (C)

$Cu^{2 +}+2Fe^{2 +}\rightleftharpoons Cu+2Fe^{3 +}$

For this reaction at equilibrium the concentration of $Cu^{2 +}$ ions is not changed by the addition of Cu as it is solid. So its molar concentration is always taken as unity.