Electrochemistry - Result Question 51
####50. A current of $3.7 A$ is passed for $6 h$ between nickel electrodes in $0.5 L$ of a $2.0 M$ solution of $Ni\left(NO _3\right) _2$. What will be the molarity of solution at the end of electrolysis?
$(1978,2 M)$
Topic 2 Conductivity of Electrolytic Solutions and their Measurement and Nernst Equation
Objective Questions I (Only one correct option)
Show Answer
Solution:
- During electrolysis, $Ni^{2+}$ will be reduced at cathode and $H _2 O$ will be oxidised at anode.
Number of Faraday’s passed $=\frac{3.7 \times 6 \times 60 \times 60}{96500}=0.828$
$\Rightarrow \quad 0.828$ g equivalent of $Ni^{2+}$ will be deposited at cathode.
Initial moles of $Ni^{2+}$ ion $=2 \times 0.5=1.0$
Moles of $Ni^{2+}$ ion remaining after electrolysis $=1.0-\frac{0.828}{2}$
$$ \begin{gathered} =0.586 \ \Rightarrow \quad \text { Molarity of } Ni^{2+} \text { in final solution }=\frac{0.586}{0.50}=1.172 M \end{gathered} $$
