Question

Hydrolysis of sucrose: \[ \ce{C_{12}H_{22}O_{11} + H2O \xrightarrow{H^+} C_6H_{12}O_6 + C_6H_{12}O_6} \] (a) Rate law equation
(b) Molecularity and order of reaction
(c) What do you call such reactions?

Hint:

If one reactant is in large excess (e.g. water), the reaction appears first-order even if two species are involved.

Answer 1

(a) Rate law: \[ \text{Rate} = k[\text{Sucrose}] \] (b) - Molecularity = 2 (Sucrose + H\(_2\)O) - Order = 1 (depends only on sucrose concentration) (c) These are called **pseudo-first-order reactions** because one reactant (water) is in large excess and treated as constant. \[ \boxed{\text{Pseudo-first-order reaction}} \]