Chemical Kinetics Question 177

Question: 75% of a first order reaction is completed in 30 minutes. What is the time required for 93.75% of the reaction (in minutes) [KCET 2001]

Options:

A) 45

B) 120

C) 90

D) 60

Show Answer

Answer:

Correct Answer: D

Solution:

$ k=\frac{2.303}{t}\log ( \frac{a}{a-x} ) $ ; $ k=\frac{2.303}{30}\log ( \frac{100}{100-75} ) $

$ k=\frac{2.303}{t}\log ( \frac{100}{100-93.75} ) $ Put the value of $ K $ from above equation we get the value of $ t $ therefore
$ \therefore \ \ \ t=60,\min . $



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