Consider the following first-order reaction: A → B. The concentration of A at the start of the reaction is 4.17 M and after 4.84 s is 3.56 M. (a) Using the integrated rate law for a first-order reaction, calculate the value of the rate constant.

Answer : The value of rate constant is,

Explanation :

First we have to calculate the rate constant, we use the formula :

Expression for rate law for first order kinetics is given by:

where,

k = rate constant  = ?

t = time passed by the sample  = 4.84 s

a = initial concentration = 4.17 M

a - x = concentration after time 4.84 s = 3.56 M

Now put all the given values in above equation, we get

Therefore, the value of rate constant is,

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