1000 mL 1 M CuSO4 (aq) is electrolysed by 9.65 amp current for 100 sec using Pt-electrode. Which is incorrect statemenet? (1) Blue colour intensity decreases during electrolysis. (2) Blue colour intensity remains constant if Cu-electrode used. (3) pH of solution is 8 after electrolysis. (4) At anode O2 gas liberated during electrolysis?

Question

Answer

Electrolysis of CuSO4 (aq)

Experimental Conditions

1000 mL of 1 M CuSO4 (aq) solution

9.65 amp current for 100 sec

Pt-electrode used

Observations

Blue colour intensity decreases during electrolysis

pH of solution is 8 after electrolysis

O2 gas liberated at the anode during electrolysis

Explanation

The blue colour of CuSO4 solution is due to the presence of Cu2+ ions. During electrolysis, Cu2+ ions are reduced to form Cu metal at the cathode. As a result, the concentration of Cu2+ ions in the solution decreases, leading to a decrease in the blue colour intensity of the solution. If a Cu-electrode were used instead of a Pt-electrode, Cu2+ ions would be reduced at the electrode surface, leading to the formation of Cu metal. The blue colour intensity of the solution would remain constant in this case.

The reduction of Cu2+ ions at the cathode results in the release of H+ ions, which increases the pH of the solution. After electrolysis, the pH of the solution is 8, indicating that the solution has become slightly basic.

At the anode, water molecules are oxidized to form O2 gas and H+ ions. The H+ ions combine with the OH- ions present in the solution to form water molecules. Hence, the overall reaction at the anode is:

2H2O(l) → O2(g) + 4H+(aq) + 4e-

Answer

Hii

Similar Class 12 Doubts

A sample of Al2O3 dissolved in a molten fluoride bath is electrolysed using a current of 1.60 .A What is the rate of production of Al in gm per hour ? The oxygen liberated at the positive carbon electrode reacts with the carbon to form CO2 . What mass of CO2 is produced per hour ?

Top Courses for Class 12

Suggested Free Tests

Related Content

Schools

Competitive Examinations

Quick Access Links

Technical Exams

Similar Class 12 Doubts

A sample of Al2​O3​ dissolved in a molten fluoride bath is electrolysed using a current of 1.60 .A What is the rate of production of Al in gm per hour ? The oxygen liberated at the positive carbon electrode reacts with the carbon to form CO2​ . What mass of CO2​ is produced per hour ?

Top Courses for Class 12

Suggested Free Tests

Related Content

A sample of Al2O3 dissolved in a molten fluoride bath is electrolysed using a current of 1.60 .A What is the rate of production of Al in gm per hour ? The oxygen liberated at the positive carbon electrode reacts with the carbon to form CO2 . What mass of CO2 is produced per hour ?