Alkanols have the general molecular formula

This question is asking about the general molecular formula of alkanols. Alkanols are a class of organic compounds that contain a hydroxyl (-OH) group attached to a saturated carbon atom. The general formula for alkanols is C_nH_2n+1OH, where "n" is the number of carbon atoms in the molecule.

The given options are different molecular formulas for alkanols, and we need to select the correct one. Option A, C₁H_2n-2, is not a valid molecular formula for any organic compound. Option B, C₁H_2n-1CHO, represents an aldehyde, which is a different class of organic compounds and not an alkanol. Option C, C₁H_2n-2OH, is not the correct formula for alkanols as it does not have enough hydrogen atoms to satisfy the valency of the carbon and oxygen atoms in the molecule.

The correct option is D, C₂H_2n+1OH, which follows the general molecular formula of alkanols, C_nH_2n+1OH, with "n" being equal to 2 in this case. Therefore, option D is the correct answer to this question.

Understanding the general molecular formula of alkanols is important in organic chemistry as it helps in predicting the physical and chemical properties of these compounds. Alkanols are commonly used as solvents, fuels, and in the production of various chemicals such as plastics, detergents, and pharmaceuticals.