(i)Litmus test – Alcohol will have no effect on the litmus paper. Carboxylic acid acid will change blue litmus paper into red.
(ii)Reaction with sodium hydrogen carbonate – Alcohol has no reaction with sodium hydrogen carbonate (NaHCO3) but in the case of Carboxylic acid it reacts with NaHCO3 which gives CH3COONa, CO2 and H2O. The reaction is evident as the carbon dioxide will turn the lime water milk

How to Distinguish Between Alcohol and Carboxylic Acid

To distinguish between alcohol and carboxylic acid, it is important to understand their chemical properties and employ appropriate tests or methods. Here's a detailed explanation on how to differentiate between these two compounds:

Chemical Structure
- Alcohol: Alcohols are organic compounds characterized by the presence of a hydroxyl (-OH) group attached to a carbon atom.
- Carboxylic Acid: Carboxylic acids are organic compounds with a carboxyl (-COOH) group attached to a carbon atom.

pH Test
- Alcohol: Alcohols are typically neutral in nature and do not exhibit acidic or basic properties. Therefore, when a pH test is conducted, alcohols will not show any significant change in pH.
- Carboxylic Acid: Carboxylic acids are acidic in nature and will exhibit a decrease in pH when a pH test is performed. The presence of carboxylic acids can be confirmed by the observed decrease in pH value.

Solubility Test
- Alcohol: Most alcohols are soluble in water, especially those with a smaller carbon chain length. However, their solubility decreases with an increase in carbon chain length.
- Carboxylic Acid: Carboxylic acids are also soluble in water due to their ability to form hydrogen bonds. However, their solubility decreases as the carbon chain length increases.

Reaction with Sodium Bicarbonate
- Alcohol: Alcohols do not react with sodium bicarbonate (NaHCO3) since they lack acidic properties.
- Carboxylic Acid: Carboxylic acids react with sodium bicarbonate to produce carbon dioxide gas (CO2), water, and a corresponding salt. Effervescence (bubbling) will be observed during this reaction.

Reaction with Acidified Potassium Dichromate
- Alcohol: Alcohols do not readily react with acidified potassium dichromate (K2Cr2O7) under normal conditions.
- Carboxylic Acid: Carboxylic acids undergo oxidation when reacted with acidified potassium dichromate, resulting in a color change from orange to green.

Odor Test
- Alcohol: Alcohols often have distinctive, pleasant odors. For example, ethanol has a characteristic smell similar to that of alcoholic beverages.
- Carboxylic Acid: Carboxylic acids have strong, pungent odors. For instance, acetic acid is responsible for the vinegar-like smell in vinegar.

By applying these tests and observations, it is possible to distinguish between alcohols and carboxylic acids based on their chemical properties, reactions, solubility, pH, and odor characteristics.