Identify the compound $(C)$ in the following reaction sequence:
$\gamma$-butyrolactone $\xrightarrow[(ii) SOCl_2]{(i) HCl} (A)$ $\xrightarrow[AlCl_3]{Ph-H} (B)$ $\xrightarrow{KOH/MeOH} (C)$

Which of the following gives the highest yield of $2$-pentene upon reaction with $C_2H_5ONa/C_2H_5OH$?

Ethyl bromide reacts with silver nitrite to form

Compound $A$ with molecular formula $C_4H_9Br$ is treated with aqueous $KOH$ solution. The rate of this reaction depends upon the concentration of compound $A$ only. When another optically active isomer $B$ of this compound was treated with aqueous $KOH$ solution,the rate of reaction was found to be dependent on the concentration of both the compound and $KOH$.
$(i)$ Write down the structural formula of both compounds $A$ and $B$.
$(ii)$ Out of these two compounds,which one will be converted to the product with inverted configuration?

Which $Cl$ atom is most susceptible to be attacked by aqueous $KOH$?

Arrange the following compounds in decreasing order of reactivity for nucleophilic substitution reaction:
$(I)$ $CH_3-CH_2-OSO_2CF_3$
$(II)$ $CH_3-CH_2-OTs$
$(III)$ $CH_3-CH(OH)-CH_3$
$(IV)$ $C_6H_5-CH(OH)-CH_3$