Question

Which of the following reactions has of overall order \(1.5\) ?

• A. \(2\text{H}_2\text{O}_{2(g)}⟶2\text{H}_2\text{O}_{(\ell )}+\text{O}_{2(g)}\)
• B. \(\text{H}_{2(g)}+\text{I}_{2(g)}⟶2\text{HI}_{(g)}\)
• C. \(\text{CH}_3\text{CHO}_{(g)}⟶\text{CH}_{4(g)}+\text{CO}_{(g)}\)
• D. \(2\text{NO}_{(g)}+2\text{H}_{2(g)}⟶\text{N}_{2(g)}+2\text{H}_2\text{O}_{(\ell )}\)

Hint:

Recall the experimental rate laws of the standard reactions.

Answer 1

The Correct Option is C

Step 1: List the experimental orders:
$\text{H}_2\text{O}_2$: 1. $\text{H}_2 + \text{I}_2$: 2. $\text{CH}_3\text{CHO}$: 3/2. $\text{NO} + \text{H}_2$: 3.

Step 2: Pick:
The only entry equal to $1.5$ is $\text{CH}_3\text{CHO}(g) \to \text{CH}_4(g) + \text{CO}(g)$, which has the rate law $r = k[\text{CH}_3\text{CHO}]^{3/2}$.

Final Answer:
The answer is option (C). \[ \boxed{\text{CH}_3\text{CHO} \to \text{CH}_4 + \text{CO}} \]