Question
If the half life of a first order reaction is 6.93 minutes then the time required for completion of 99% of the reaction will be _____ minutes. (Given : 2 = 0.3010)
JEE Main
Chemistry
Chemical Kinetics
2026
JEE Main 2026 (05 April Shift 1)
JEE Main Chemistry Question (2026) — Solution
Options
- A. A
- B. B
- C. C
- D. D
Answer
A. A
Step-by-step solution
For a first-order reaction, the rate constant k is given by: k = 2.303 2 t_ 1/2 Using the standard approximation 2.303 2 0.693: k = 0.693 6.93 = 0.1 min ^ -1 The time required for 99\% completion of the reaction is given by the integrated rate law: t = 2.303 k ( a a - x ) Here, the initial concentration a = 100 and the amount reacted x = 99, so a - x = 1. t = 2.303 0.1 ( 100 1 ) t = 23.03 (10^2) t = 23.03 2 = 46.06 minutes Answer: 46.06
Related: Chemistry — Chemical Kinetics · All PYQ Banks