Question

Half-life period of a first reaction, $A$ $\to$ product is 6.93 h. What is the value of rate constant?

• A. 1.596 h${}^{-1}$
• B. 0.1 h${}^{-1}$
• C. 4.802 h${}^{-1}$
• D. 10 h${}^{-1}$

Answer 1

Answer: (B)

0.1 h${}^{-1}$

The formula for the half-life of $1^{st}$ order reaction is

Half life, $t_{1/2}=\frac{0.693}{k}$

$k=\frac{0.693}{t_{1/2}}$

$k=\frac{0.693}{6.93}$

$k=0.1h^{-1}$