Electrochemistry 1 Question 2

2. A solution of $\mathrm{Ni}(\mathrm{NO} _{3}) _{2}$ is electrolysed between platinum electrodes using $0.1$ Faraday electricity. How many mole of $\mathrm{Ni}$ will be deposited at the cathode?

(2019 Main, 9 April II)

(a) $0.20$

(b) $0.10$

(c) $0.15$

(d) $0.05$

Show Answer

Answer:

Correct Answer: 2. (d)

Solution:

  1. A solution of $\mathrm{Ni}(\mathrm{NO} _{3}) _{2}$ is electrolysed between platinum electrodes using $0.1$ Faraday electricity. It means that $0.1$ equivalent of $\mathrm{Ni}^{2+}$ will be discharged.

Electrolysis of $\mathrm{Ni}(\mathrm{NO} _{3}) _{2}$ gives

$ \mathrm{Ni}^{2+}+2 e^{-} \longrightarrow \mathrm{Ni} \quad(\text { Atomic mass of } \mathrm{Ni}=58.7) $

Number of equivalents $=$ Number of moles $\times$ number of electrons.

$0.1=$ Number of moles $\times 2$

$\therefore$ Number of moles of $\mathrm{Ni}=\frac{0.1}{2}=0.05$