Q.
If 60% of a first order reaction was completed in 60 minutes, 50% of the same reaction would be completed in approximately (log 4 = 0.60, log 5 = 0.69)
A) 45 minutes
B) 60 minutes
C) 40 minutes
D) 50 minutes
Explanation
[Solution from source] k = (2.303/60) log(100/40) = (2.303/60)(0.69 − 0.30) ≈ 0.0150 min⁻¹. t½ = 0.693/0.0150 ≈ 46 min, closest to 45 minutes. 50 minutes assumes a linear (zero-order) fall. Answer (1).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.