Question

For a first order A → B, the reaction rate at reactant concentration of 0.01 m is found to be 2.0 × 10^–5. The half-life period of reaction.

Options

• 30 s

• 220 s

• 300 s

• 347 s

Answer 1

347 s

Explanation:

A → B

Rate of reaction = 2.0 × 10^–5 mol^–1 sec^–1

Order of reaction (n) = 1

Rate = K[A]ⁿ = K[A]

K = `"rate"/([A]) = ((2 xx 10^5  mol  L^-1 S^-1))/(0.01  mol^(L - 1)) = 2 xx 10^3  5^-1`

`1/2 = 0693/K = 0.693/(2 xx 10^2  5^-1)` = 347 sec.