Identify the reagent used in the following conversion:
$CH_3CH_2Cl \xrightarrow{A} CH_3CH_2NO_2$ (Nitroethane)

In nucleophilic aliphatic substitution,the nucleophiles are generally

The mechanism of $S_{N}1$ reaction is given as:
$R-X$ $\rightarrow R^{\oplus} X^{\ominus}$ $\rightarrow R^{\oplus} | X^{\ominus}$ $\xrightarrow{Y^{\ominus}} R-Y + X^{\ominus}$
(Ion pair) (Solvent separated ion pair)
$A$ student writes general characteristics based on the given mechanism as:
$(a)$ The reaction is favoured by weak nucleophiles
$(b)$ $R^{\oplus}$ would be easily formed if the substituents are bulky
$(c)$ The reaction is accompanied by racemization
$(d)$ The reaction is favoured by non-polar solvents.
Which observations are correct?

Which among the following reactions does not occur?

Which one of the following compounds will give a $Saytzeff$ alkene as the major product in an elimination reaction?

The major product obtained in the following reaction is $C_2H_5ONa + (CH_3)_3C-Cl \rightarrow$