If time required for 90 % completion of a first order reaction is ' t '. What is the time required for 99.9 % completion of reaction at same temperature?

Step-by-step solution

For a first order reaction, the time required for completion is given by t = 2.303 k ( a a-x ) For 90 % completion, x = 0.9a t_ 90 % = 2.303 k ( a a - 0.9a ) = 2.303 k 10 = 2.303 k Given t_ 90 % = t , so t = 2.303 k For 99.9 % completion, x = 0.999a t_ 99.9 % = 2.303 k ( a a - 0.999a ) = 2.303 k 1000 = 2.303 k 3 Substituting the value of t , we get t_ 99.9 % = 3t Answer: 3t