JEE Chemistry 2025 Question with Solution

Given: Four statements are given and we must identify the incorrect one.

Find: The incorrect statement.

1. $PH_3$ shows lower proton affinity than $NH_3$ — this is true.
2. $PF_3$ exists but $NF_5$ does not — this is true because nitrogen cannot expand its octet.
3. $NO_2$ can dimerise easily — this is true because it has an unpaired electron and forms $N_2O_4$.
4. $SO_2$ can act as an oxidizing agent, but not as a reducing agent — this is incorrect.

$SO_2$ can behave as both an oxidizing agent and a reducing agent depending on the reacting species. Therefore statement 4 is the incorrect statement.

The correct option is D.

Given: Statements involving $PH_3$, $NH_3$, $PF_3$, $NF_5$, $NO_2$ and $SO_2$.

Find: Which statement is incorrect.

• Statement 1: $PH_3$ has lower proton affinity than $NH_3$. This is correct because $NH_3$ is more basic and accepts a proton more readily.
• Statement 2: $PF_3$ exists but $NF_5$ does not. This is correct because nitrogen cannot expand its octet to form $NF_5$.
• Statement 3: $NO_2$ can dimerise easily. This is correct because $NO_2$ contains an unpaired electron and readily forms $N_2O_4$.
• Statement 4: $SO_2$ can act as an oxidizing agent, but not as a reducing agent. This is incorrect because $SO_2$ can undergo both oxidation and reduction, so it can act as both types of agent.

Therefore, the incorrect statement is $SO_2$ can act as an oxidizing agent, but not as a reducing agent, so the correct option is D.