A first order reaction is 75 % completed in 60 minutes, the time required for it's 50 % completion is.

Step-by-step solution

i. [ A ]₀=100, [ ~A ]_ t =100-75=25, t =60 ~min For first order reaction, k = 2.303 t ₁₀ [ A ]₀ [ ~A ]_ t k = 2.303 60 ~min ₁₀ 100 25 k = 2.303 0.6020 60 ~min =0.0231 ~min ⁻¹ ii. The time required for 50 % completion of reaction is, t _ 1 / 2 = 0.693 0.0231 ~min ⁻¹ =30 ~min