Question

A current of 3.53 A is passed through a Ni(NO3)2 solution for 1.70 hours. How much nickel is plated out of the solution?

Answer 1

Firstly we need to get Coulomb from Ampere as:

3.53 A x 1.70 hours x (3600 sec / 1 hour) = 21603.6 C

Now,

To get moles of electron we would solve as:

21603.6 C / 96485 Cmol^-1 electron = 0.224 moles electron

The equation will be as: Ni²⁺ + 2e^- ---> Ni

In order to get moles , we need to divide the moles of electrons by 2 (since Ni²⁺ needed 2 electrons per ion to neutralize and plate out as we can see from the equation)

So, 0.224 moles electron / 2 electron = 0.112 mol Ni

Again, we know molar mass of Nickel (NI) is 58.6934 g/mol

Thus, 0.112 mol Ni x( 58.6934 g Ni / 1 mol Ni) = 6.57 g Ni

Hence, amount of nickel plated out of the solution = 6.57 g