MHT CET Chemistry Question (2026) — Solution

Step-by-step solution

For a first order reaction, the rate constant k is given by the formula: k = 2.303 t _ 10 ( [A]_0 [A]_t ) Given that 20\% concentration remains after 10 min, we have: t = 10 min [A]_t = 20 100 [A]_0 = 0.2 [A]_0 Substituting these values into the formula: k = 2.303 10 _ 10 ( [A]_0 0.2 [A]_0 ) k = 2.303 10 _ 10 (5) Given _ 10 (5) = 0.6989: k = 2.303 10 0.6989 k = 0.2303 0.6989 k = 0.1609 min^ -1