Identify the compound that undergoes $S_{N}1$ mechanism most rapidly.

Hydrolysis of a gem-dihalide gives $....$.

Given below are two statements :
Statement $I$ : $S_N2$ reactions are 'stereospecific',indicating that they result in the formation of only one stereo-isomer as the product.
Statement $II$ : $S_N1$ reactions generally result in the formation of product as racemic mixtures.
In the light of the above statements,choose the correct answer from the options given below :

Among the following,the one which reacts most readily with ethanol is

The correct order of the rate of dehydrohalogenation of the following halides in the presence of alcoholic $KOH$ is:

Compare the relative rate of reaction with $H_2O$ for the following compounds: