Explanation

(b)
$c_{12}H_{22}O_{11} + H_{2}O\overset{Dil.acid}{\rightarrow}C_{6}H_{12}O_{6} + C_{6} + H_{12}O_{6}$
Excess glucose fructose
when one of the reactant is present in large excess, the second order reaction confirms to the first order and is knows as Pseudo-unimolecular reaction