Question

It was found that a solution of cane sugar was hydrolysed to the extent of $25$% in $1$ hr. Calculate the time taken for the sugar to be $50$% hydrolysed assuming that the reaction is of first order.

Answer 1

Since hydrolysis of sugar is first order reaction
So, $k=\frac{1}{t}\ln \frac{A_0}{A}$

$⟹k=\frac{2.303}{1}\log \frac{4}{3}$
$⟹k=2.303\times 0.125=0.287$

Now $t_{1/2}=\frac{0.693}{0.287}=2.41$ hrs = 144.6 minutes