Homologous series of alkanols have a general formula

The correct option is C_nH_2n+2O.

An alkanol (also known as an alcohol) is an organic compound containing a hydroxyl (-OH) group bonded to an alkyl group.
To understand its general formula, let us break down its components:

1. An alkyl group is derived from an alkane by removing one hydrogen atom. The general formula for an alkane is:
$$C_n{H}_{2n+2}$$

2. When we replace one hydrogen atom from the alkane with a hydroxyl group (-OH), we get the formula:
$$C_n{H}_{2n+1}OH$$

3. If we combine all the hydrogen atoms together in the molecular formula, we add the 1 hydrogen from the -OH group back to the (2n + 1) hydrogens of the alkyl chain:
$$(2n+1)+1=2n+2$$

4. This gives the consolidated general molecular formula for alkanols as:
$$C_n{H}_{2n+2}O$$

For example, for methanol (n = 1), the formula is C₁H₄O (or CH₃OH). For ethanol (n = 2), the formula is C₂H₆O (or C₂H₅OH). Both strictly fit the general formula C_nH_2n+2O.