Arrange the following halides in the decreasing order of their reactivity towards $S_{N^1}$ reaction.
$(I) \ CH_3CH_2CH_2Cl$ $(II) \ CH_2 = CH - CH(Cl)CH_3$
$(III) \ CH_3CH_2CH(Cl)CH_3$

At $30\,^\circ C$,the rate of reaction between $2$-bromobutane and $OH^-$ in $75\%$ ethanol and $25\%$ water is given by: $\text{Rate} = 3.20 \times 10^{-5} [2\text{-bromobutane}][OH^-] + 1.5 \times 10^{-6} [2\text{-bromobutane}]$. If $[OH^-] = 1.0\,M$,what percentage of the reaction proceeds via the $S_N2$ mechanism?

$A$ bottle containing $C_6H_5I$ and $C_6H_5CH_2I$ has lost its label. To identify them,samples $A$ and $B$ are taken in separate test tubes and boiled with $NaOH$ solution. Finally,the solution in each test tube is acidified with dilute $HNO_3$ and then a few drops of $AgNO_3$ solution are added. Substance $B$ gives a yellow precipitate. Which statement is correct for this process?

Explain retention,inversion,and racemization with an example of $CH_3CH(X)C_2H_5$.

An unknown compound $A$ has the molecular formula $C_5H_9Cl$. It does not react with $Br_2 / CCl_4$. When treated with a strong base,it gives a compound $B$ with the molecular formula $C_5H_8$,which reacts with $Br_2 / CCl_4$. Ozonolysis of $B$ followed by treatment with dimethyl sulfide gives a compound with the molecular formula $C_5H_8O_2$. What is the structure of $A$?

Tertiary alkyl halides are practically inert to $SN^2$ mechanism because of....