Question

Pure hydrogen is obtained by carrying electrolysis of
(A) Water containing ${H_2}S{O_4}$
(B) Water containing $NaOH$
(C) $Ba{(OH)_2}$ solution
(D) $KOH$ solution

Answer 1

Electrolysis is defined as a process of decomposing ionic compounds into their elements by passing a direct electric current through the compound in a fluid form. The cations are reduced at cathode and anions are oxidized at the anode.

Complete step by step solution:
In the process of electrolysis, there is an interchange of ions and atoms due to the addition or removal of electrons from the external circuit. Basically, on passing current, cations move to the cathode, take electrons from the cathode (given by the supply source-battery), and are discharged into the neutral atom. The neutral atom, if solid, is deposited on the cathode, and if gas, move upwards. This is a reduction process and the cation is reduced at the cathode.
At the same time anions, give up their extra electrons to the anode and are oxidized to neutral atoms at the anode. Electrons released by the anions travel across the electrical circuit and reach the cathode completing the circuit. Electrolysis involves a simultaneous oxidation reaction at the anode and a reduction reaction at the cathode.
Pure hydrogen is obtained by the electrolysis of $Ba{(OH)_2}$ solution in a U-tube using a nickel electrode. The gas is liberated at the cathode and is passed over heated platinum gauze to remove oxygen if present as an impurity.

Note:
Cell potential: The minimum potential needed for the electrolysis process depends on their ability of the individual ions to absorb or release electrons. This ability is measured as an electrode potential of the ions present in the electrolytic cell. The cell potential is the sum of the potential required for the reduction and oxidation reaction.