Question

A solution of Ni(NO₃)₂ is electrolysed between platinum electrodes using a current of 5 amperes for 20 minutes. What mass of Ni is deposited at the cathode?

Answer 1

What is electrolysis: Electrolysis is the method of passing of a direct current through an ionisable substance that is either in fused  or dissolved in a suitable solvent, generating chemical reactions at the electrodes and a separation and collection of the materials.

The main components are:An electrolyte: it is a medium and a substance, frequently an ion-conducting polymer that contains free ions, which carry electric current in the electrolyte.

A direct current (DC) electrical supply source: provides the energy necessary to create or discharge the ions in the electrolyte.

Two electrodes: which are electrical conductors.

Solution of the problem:Given,Current = 5A,Time = 20 × 60 = 1200 s.

Charge = current × time= 5 × 1200= 6000 C.

According to the reaction,Nickel deposited by 2 × 96487 C = 58.71 g.

Therefore, nickel deposited by 6000 C = (58.71 X 6000) / (2 X 96487) g= 1.825 g.

Hence, 1.825 g of nickel will be deposited at the cathode.

Answer 2

Hey !!

Quantity of electricity passed = I × t = ( 5 A ) × (20 × 60s)

             = 6000 C

The electrode reaction is Ni²⁺ + 2e⁻ ------> Ni

2 × 96500 C deposit Ni = 58.7 g

           ∴ 6000 C will deposit Ni = 58.7 / 2 × 96500 × 6000

        = 1.825 g

Hope it helps you !!