MHT CET Chemistry Question (2026) — Solution

Step-by-step solution

For a first order reaction, the amount of reactant remaining after n half-lives is given by N_t = N_0 2^n Given initial amount N_0 = 10 g and final amount N_t = 2.5 g Substituting the values, 2.5 = 10 2^n 2^n = 10 2.5 = 4 2^n = 2^2 n = 2 Total time required t = n t_ 1/2 Given t_ 1/2 = 5 hour t = 2 5 = 10 hour Answer: 10 hour