At a certain temperature the rate of this reaction is first order in hi with a rate constant of : 0.0632s2hig=h2g+i2g suppose a vessel contains hi at a concentration of 1.28m . calculate how long it takes for the concentration of hi to decrease to 17.0% of its initial value. you may assume no other reaction is important. round your answer to 2 significant digits.

Explanation:

Whenever a question asks you, "How long does it take to reach a certain concentration?" or something like that, you must use the appropriate integrated rate law expression.

The integrated rate law for a first-order reaction is  

Data:

[A]₀ = 1.28 mol·L⁻¹

[A] = 0.17 [A]₀

  k = 0.0632 s⁻¹

Calculation:

the ratio of the conjugate base to the acid required to attain the desired ph.