JEE Main 2023 — Electrochemistry Question with Solution

Using the Faraday's law of electrolysis, we can directly relate the amount of substance deposited (in this case, the nickel layer) with the electric charge passed through the electrolyte.

The formula for Faraday's law of electrolysis is:

$$W=z\times i\times t$$

where W is the amount of substance deposited (in grams), z is the electrochemical equivalent (grams per coulomb), i is the current (in amperes), and t is the time (in seconds).

By relating the density and volume of the nickel layer to the electric charge passed through the electrolyte, we can calculate the time needed for the deposition:

$$10\times 100\times 0.0001=\frac{\left(\frac{\text{ atomic wt. }}{\text{ v.f }}\right)\times 2\times x}{96500}$$

where v.f is the valence factor for the reaction (in this case, 2).

Solving for x, we get:

$$x=161\sec$$

So, the value of x is 161 seconds.