Haloalkanes can be represented by the formula

$C_nH_{2n+1}X$

The correct answer is Option (2) → $C_nH_{2n+1}X$

Haloalkanes are derived from saturated hydrocarbons (alkanes) by replacing one hydrogen atom with a halogen atom (X, where X can be F, Cl, Br, or I).

1. Formula of Alkanes

The general formula for an alkane (saturated hydrocarbon) is $C_n​H_{2n+2​}$.

2. Formula of Haloalkanes

To form a haloalkane, one hydrogen atom is removed from the alkane molecule, and one halogen atom (X) is added.

• Alkane: $C_n​H_{2n+2​}$
• Remove one H: $C_n​H_{(2n+2)−1}​=C_n​H_{2n+1​}$
• Add one X: $C_n​H_{2n+1}​X$

The general formula for a mono-haloalkane is $C_n​H_{2n+1}​X$.