Given below are two statements :
1 M aqueous solution of each of , are electrolysed using inert electrodes,
Given : , and
Statement (I) : With increasing voltage, the sequence of deposition of metals on the cathode will be and Cu
Statement (II) : Magnesium will not be deposited at cathode instead oxygen gas will be evolved at the cathode.
In the light of the above statement, choose the most appropriate answer from the options given below
1 M aqueous solution of each of , are electrolysed using inert electrodes,
Given : , and
Statement (I) : With increasing voltage, the sequence of deposition of metals on the cathode will be and Cu
Statement (II) : Magnesium will not be deposited at cathode instead oxygen gas will be evolved at the cathode.
In the light of the above statement, choose the most appropriate answer from the options given below
- (A)Both statement I and statement II are incorrect
- (B)Statement I is correct but statement II is incorrect✓ Correct
- (C)Both statement I and statement II are correct
- (D)Statement I is incorrect but statement II is correct
Answer: (B)
Solution
At the cathode the ion with the higher reduction potential is discharged first, and as the applied voltage is raised the metals come out in that order. Silver at V leads, mercury at V follows, and copper at V comes next, so this sequence is right. Magnesium, with a strongly negative reduction potential of V, is far harder to reduce than water, so rather than magnesium being deposited it is water that is reduced at the cathode, releasing hydrogen; oxygen appears at the anode, not the cathode. The first statement is correct while the second is incorrect.
JEE Main · 2025 · 07 Apr 2025 · Shift 2 · Single correct option