Nitrous acid (HNO2) slowly decomposes to NO, NO2, and water by the following second-order reaction: 2 HNO2(aq) ---> NO(g) + NO2(g) + H2O(l) Use the date below to determine the rate law and the constant for this reaction: Time (s) [HNO2] (um) 0 0.1560 1000 0.1466 1500 0.1424 2000 0.1383 2500 0.1345 3000 0.1309 A) Rate = ?? B) k = ??? /uM*s C) Determine the half-life for the decomposition of HNO2: t1/2 = ?

Respuesta :

Answer:

The rate law of the reaction will be given as;

[tex]R=k[HNO_2]^2[/tex]

The value of rate constant of the reaction is :

[tex]k=4.11\times 10^{-4} \mu M^{-1}s^{-1}[/tex]

The half life for the decomposition of [tex]HNO_2[/tex] is 15,596.73 s

Explanation:

[tex]2HNO_2(aq)\rightarrow NO(g) + NO_2(g) + H_2O(l)[/tex]

Given that reaction follows second order kinetics;

The rate law of the reaction will be given as;

[tex]R=k[HNO_2]^2[/tex]

Integrated rate law for second order kinetics is given by:

[tex]\frac{1}{A}=kt+\frac{1}{A_o}[/tex]

[tex]A_o[/tex] = initial concentration

A = concentration left after time t

k = rate constant of the reaction

Concentration at 0 second:

[tex]A_o=0.1560 \mu M[/tex]

Concentration at 1000 second:

[tex]A=0.1466 \mu M[/tex]

t = 1000 s - 0 s = 1000 s

[tex]\frac{1}{0.1466 \mu M}=k\times 1000 s+\frac{1}{0.1560 \mu M}[/tex]

[tex]k\times 1000 s=\frac{1}{0.1466 \mu M}-\frac{1}{0.1560 \mu M}[/tex]

[tex]k=4.11\times 10^{-4} \mu M^{-1}s^{-1}[/tex]

Half life for second order kinetics is given by:

[tex]t_{\frac{1}{2}=\frac{1}{k\times A_o}[/tex]

So, the half life for the decomposition of [tex]HNO_2[/tex]:

[tex]t_{\frac{1}{2}=\frac{1}{4.11\times 10^{-4} \mu M^{-1}s^{-1}\times0.1560 \mu M}[/tex]

[tex]t_{1/2}=15,596.73 s[/tex]

The half life for the decomposition of [tex]HNO_2[/tex] is 15,596.73 s