Question

For the reaction $2NO\left(g\right)+H_2\left(g\right)\to N_{2}O\left(g\right)+H_{2}O\left(g\right),$ at 900 K following data are observed.
Find out the order of reaction.

Initial pressure of NO (atm)	Initial pressure of $H_2$ (atm)	Initial rate of pressure decrease (atm $mi{n}^{-1}$)
0.150	0.40	0.020
0.075	0.40	0.005
0.150	0.20	0.010

• A. 3
• B. 2
• C. 1
• D. 0

Answer 1

The correct option is A 3

From experiment I and II, $\left[H_2\right]$ is constant and [NO] is doubled. Then rate becomes 4 times.
So order of reaction w.r.t. (NO) = 2.
From experiment I and III, [NO] is constant and $\left[H_2\right]$ is doubled then rate becomes 2 times. So order of reaction w.r.t. $\left(H_2\right)$ = 1.
Total order = 3.