Question

Assertion
When acidified zinc sulphate solution is electrolysed between zinc electrodes, it is zinc that is deposited at the cathode and hydrogen evolution does not take place.
Reason
The electrode potential of zinc is more negative than hydrogen as the over voltage for the hydrogen evolution on zinc is quite large.
A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
B. Both Assertion and Reason are correct but reason is not the correct explanation for Assertion
C. Assertion is correct but reason is incorrect
D. Assertion is incorrect but Reason is correct.

Answer 1

Hint: In nature one form of energy can be converted to another form, while it cannot be destroyed. This is known as the law of conservation of energy. Just like other forms of energy, chemical energy can also be converted into electrical energy. For this conversion, an apparatus called the galvanic cell.

Complete step by step answer:
Energy can only be converted from one form to another, galvanic cells are used for the conversion of chemical energy to chemical energy.
The principle of a galvanic cell is the potential difference between the electrodes and the electrolyte that is present in between them. This potential difference makes the electrons move in the cell and produce electricity.
The main source of the electricity produced in the redox reaction that happens inside the galvanic cell. The two portions of the cell are called the half cells or redox cou3ple. Reduction takes in one of the half-cells while oxidation happens in the other.
Oxidation takes place at the anode while the reduction happens at the cathode.
In the above-given cell, zinc is having a lower standard reduction potential than hydrogen, so the oxidation of zinc takes place at the anode while hydrogen is reduced at the cathode, this fact is against the assertion given hence the assertion is wrong.
But the fact stated in the reason matches the given fact so the reason is correct

So, the correct answer is Option D .

Note: The potential of the individual half-cell cent is measured, we can only measure the difference between the two half cells which appears as the electromotive force (emf) and produces current. For the measurement of the individual half-cell potential, we use the standard hydrogen electrode since we take the potential of hydrogen as zero.