# Problem: The half-life for the second-order decomposition of HI is 15.4 s when the initial concentration of HI is 0.67 M. What is the rate constant for this reaction?A. 9.7 x 10-2M-1s-1B. 4.5 x 10-2M-1s-1C. 3.8 x 10-2M-1s-1D. 2.2 x 10-2M-1s-1E. 1.0 x 10-2M-1s-1

###### FREE Expert Solution
91% (166 ratings)
###### FREE Expert Solution

We’re being asked to calculate the rate constant (k) of a second-order reaction with a half-life of 15.4 s at an initial concentration of 0.67 M.

Recall that half-life (t1/2) is the time needed for the amount of a reactant to decrease by 50% or one-half

The half-life of a second-order reaction is given by:

$\overline{){{\mathbf{t}}}_{\mathbf{1}\mathbf{/}\mathbf{2}}{\mathbf{=}}\frac{\mathbf{1}}{\mathbf{k}{\mathbf{\left[}\mathbf{A}\mathbf{\right]}}_{\mathbf{0}}}}$

where:

k = rate constant

[A]0 = initial concentration

91% (166 ratings) ###### Problem Details

The half-life for the second-order decomposition of HI is 15.4 s when the initial concentration of HI is 0.67 M. What is the rate constant for this reaction?

A. 9.7 x 10-2M-1s-1

B. 4.5 x 10-2M-1s-1

C. 3.8 x 10-2M-1s-1

D. 2.2 x 10-2M-1s-1

E. 1.0 x 10-2M-1s-1

What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the Integrated Rate Law concept. You can view video lessons to learn Integrated Rate Law. Or if you need more Integrated Rate Law practice, you can also practice Integrated Rate Law practice problems.

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Based on our data, we think this problem is relevant for Professor Parnis' class at Trent University.