The number of possible isomeric products formed when $3$-chloro-$1$-butene reacts with $HCl$ through carbocation formation is $.............$.

In which of the following compounds does the carbon atom attached to the halogen possess $sp^2$ hybridization?

Match the reactions in List-$I$ with the major products in List-$II$:
| List-$I$ | List-$II$ (Major Product) |
| :--- | :--- |
| $(A)$ $CH_3-CHBr-CH_2Br \xrightarrow{KOH/C_2H_5OH}$ | $(I)$ $1^{\circ}$-alkyl bromide |
| $(B)$ $CH_3-CH_2-CH=CH_2 \xrightarrow{HBr, (C_6H_5CO)_2O_2, \Delta}$ | $(II)$ $2^{\circ}$-alkyl bromide |
| $(C)$ $CH_3CH_2CH_3 \xrightarrow{Br_2, h\nu}$ | $(III)$ Allyl bromide |
| $(D)$ $CH_3-CH=CH_2 \xrightarrow{NBS, \Delta}$ | $(IV)$ Alkenyl bromide |

Assertion : Alkylbenzene is not prepared by Friedel-Crafts alkylation of benzene.
Reason : Alkyl halides are less reactive than acyl halides.

Match the reactions given in Column-$I$ with the types of reactions given in Column-$II$.

Complete the following reactions:
$(1)$ Isopropyl bromide $\xrightarrow[{KOH, \Delta}]{{\text{alcoholic}}} X$ $\xrightarrow[{peroxide}]{{HBr}} Y$
$(2)$ $n$-propyl alcohol $\xrightarrow[{443 \ K}]{{\text{Conc. } H_2SO_4}} X$ $\xrightarrow{{HBr}} Y$