Question

Which of the following reactions is NOT an example of redox reaction?

• A. \(\text{Cl}_2+2\text{H}_2\text{O}+\text{SO}_2⟶4\text{H}^++\text{SO}_4^{2-}+2\text{Cl}^-\)
• B. \(\text{Cu}^{2+}+\text{Zn}⟶\text{Cu}+\text{Zn}^{2+}\)
• C. \(2\text{H}_2+\text{O}_2⟶2\text{H}_2\text{O}\)
• D. \(\text{HCl}+\text{H}_2\text{O}⟶\text{H}_3\text{O}^++\text{Cl}^-\)

Hint:

In a redox reaction oxidation numbers change; ionisation of HCl in water has no such change.

Answer 1

The Correct Option is D

Step 1: Assign oxidation numbers on each side
Check every element in each equation, left side then right side.

Step 2: Compare
Reactions A, B and C each show an element gaining or losing electrons. In D, HCl simply donates a proton to water and nothing changes oxidation state. So D is the non-redox one.

Final Answer:
The proton transfer in option (D) involves no oxidation number change. \[ \boxed{\text{(D)}} \]