The rate law for the reaction R C l + N a O H ( a q ) → R O H + N a C l is given by Rate = k [ R C l ] . The rate of the reaction will be

Step-by-step solution

It is a pseudo-first-order reaction (molecularity is two but of first order) as the rate of reaction does not depend upon the concentration of aqueous NaOH as it is in excess so no effect of change of concentration of it. Since r ∝ [RCl], so rate is halved when the concentration of alkyl halide is halved.