Question

A certain peroxide is deactivated by addition of an acid. The reaction is found to follow first order rate law with respect to peroxide concentration. Initially 10% of the peroxide was found to be deactivated in one minute. The time required for 50% of peroxide to be deactivated would be

• A. 10 min
• B. 6.93 min
• C. 69.3 min
• D. 69.3 sec

Answer 1

The correct option is B 6.93 min

For 10% completion, $k=\frac{2.303}{1}log\frac{100}{90}$. For $50\%k=\frac{0.693}{t}$ Equation the RHS, solution for t50% can be obtained. For simplification, simplified log table given under synopsis can be used.