Question

Which of the following is an example of a redox reaction?

• A. NaCl dissolving in water
• B. 2H$_2$O$_2$ (aq) $\to$ 2H$_2$O (l) + O$_2$ (g)
• C. NaOH dissolving in water
• D. CaCO$_3$ (s) $\to$ CaO (s) + CO$_2$ (g)

Hint:

In a redox reaction, one species is reduced (gains electrons) and another is oxidized (loses electrons).

Answer 1

The Correct Option is B

A redox reaction involves the transfer of electrons between species. In the reaction: \[ 2\text{H}_2\text{O}_2 (aq) \to 2\text{H}_2\text{O} (l) + \text{O}_2 (g) \] Hydrogen peroxide (H$_2$O$_2$) undergoes both reduction and oxidation. The oxygen atoms in hydrogen peroxide are reduced and oxidized, respectively, leading to the formation of water and oxygen gas. Answer: The reaction \(2\text{H}_2\text{O}_2 \to 2\text{H}_2\text{O} + \text{O}_2\) is a redox reaction, so the correct answer is option (2).