Question

The following reaction occurs in aqueous solution: NH4 + (aq) + NO2 - → N2 (g) + 2H2O (l) The data below is obtained at 25°C. [NH4 +] (M) [NO2 -] (M) Initial rate (M/s) 0.0100 0.200 3.2 × 10-3 0.0200 0.200 6.4 × 10-3 The order of the reaction in NH4 + is __________.

Answer 1

Answer: The order with respect to $NH_4^+$ is 1.

Explanation:

Rate law says that rate of a reaction is directly proportional to the concentration of the reactants each raised to a stoichiometric coefficient determined experimentally called as order.

$NH_4^++NO_2^-\rightarrow N_2+2H_2O$

$Rate=k[NH_4^+]^x[NO_2^-]^y$

k= rate constant

x = order with respect to $NH_4^+$

y = order with respect to A$NO_2^-$

n = x+y = Total order

From trial 1: $3.2\times 10^{-3}=k[0.0100]^x[0.200]^y$    (1)

From trial 2: $6.4\times 10^{-3}=k[0.0200]^x[0.200]^y$    (2)

Dividing 2 by 1 :$\frac{6.4\times 10^{-3}}{3.2\times 10^{-3}}=\frac{k[0.0100]^x[0.2000]^y}{k[0.0200]^x[0.200]^y}$

$2=2^x,2^1=2^x$ therefore x=  1

Thus order with respect to $NH_4^+$ is 1.