A current of 1.40 ampere is passed through 500mL of 0.180M solution of zinc sulphate for 200 seconds. The molarity of Zn2+ ions after deposition of zinc is:

 The equation is given by

Zn2++ 2e− ⟶ Zn

Faraday = Charge/96500 =1.40×200/96500 = 2.90×10−3 mol

∴Zn deposited =2.90×10−3/2 =1.45×10−3 mol

Now, mol of Zn2+ initially =0.180×0.5

Molarity × V = 0.09 mol

mol of Zn2+ left after deposition =0.09 − 0.00145 = 0.08855 mol

Molarity = Moles/Volume = 0.08855/0.5 = 0.177 M

When an electrolyte, such as metal sulphate, is dissolved in water, the molecules split into positive and negative ions. The positive ions proceed to the electrodes connected to the negative terminal of the battery, where they absorb electrons and transform into a pure metal atom, which is then put on the electrode. Negative ions flow to the electrode connected to the positive end of the battery, giving up their excess electrons and transforming into pure metal atoms