JEE Chemistry 2025 Question with Solution

Given: A $0.1 \, \text{M}$ KI solution reacts according to

Find: Which among statements (A) to (D) are correct.

For $200 \, \text{mL} = 0.2 \, \text{L}$ of $0.1 \, \text{M}$ KI, moles of iodide are

From the balanced reaction, $5$ moles of $I^-$ react with $1$ mole of $IO_3^-$. Therefore, required moles of KIO$_3$ are

So statement (A) is correct.

For acid requirement, $5$ moles of $I^-$ need $6$ moles of $H^+$. Hence for $0.02 \, \text{mol}$ of $I^-$,

Since each $H_2SO_4$ gives $2H^+$, required moles of $H_2SO_4$ are

Therefore statement (B) is false.

For $0.5 \, \text{L}$ of $0.1 \, \text{M}$ KI, moles of $I^-$ are

From the reaction, $5$ moles of $I^-$ produce $3$ moles of $I_2$. Thus,

So statement (C) is false. The solution also indicates a discrepancy with one approach that mentioned $0.005 \, \text{mol}$, but the detailed stoichiometric calculation gives $0.03 \, \text{mol}$, which is consistent with the balanced equation.

For KIO$_3$, the iodate ion undergoes a $5$-electron change in this redox process. Therefore, its equivalent weight is

Hence statement (D) is correct.

Therefore, the correct statements are (A) and (D) only. The correct option is A.

Given: Statements must be checked using the reaction stoichiometry. Find: Which statements are true.

1. Statement (A):

Using

we get

So (A) is true.

2. Statement (B): Using

for $0.02 \, \text{mol}$ of $I^-$,

Hence,

So (B) is false.

3. Statement (C):

Using

we get

So (C) is false.

4. Statement (D): Equivalent weight in a redox reaction is molecular weight divided by the number of electrons involved per formula unit. For KIO$_3$, this number is $5$. Therefore,

So (D) is true.

Thus, only statements (A) and (D) are correct, so the correct option is A.