JEE Main 2024 Chemistry question
r = k[A] for a reaction, 50% of A is decomposed in 120 minutes. The time taken for 90% decomposition of A is minutes.
Answer: 399
Solution
For a first-order reaction t₉₀ = (2.303/k)log 10 and t₅₀ = (2.303/k)log 2 = 120 min. So t₉₀ = 120 × (1/0.3010) = 398.67 ≈ 399 minutes.