Question

For the given first order reaction A → B the half life of the reaction is 0.3010 min. The ratio of the initial concentration of reactant to the concentration of reactant at time 2.0 min will be equal to ______. (Nearest integer)

Options

• 95

• 105

• 100

• 69

Answer 1

For the given first order reaction A → B the half life of the reaction is 0.3010 min. The ratio of the initial concentration of reactant to the concentration of reactant at time 2.0 min will be equal to 100.

Explanation:

For first order reaction;

k = `2.303/"t" log  ["A"_0/"A"_"t"] => 0.693/"t"_(1//2) = 2.303/2 log ("A"_0/"A"_"t")`

`=> (2.303 xx 0.3010)/0.3010 = 2.303/2 log  "A"_0/"A"_"t"`

`log  "A"_0/"A"_"t" = 2`

∴ `"A"_0/"A"_"t" = 10^2 = 100`