Which of the following does NOT describe a property of ethanol (C₂H₅OH)?

The correct option is: It turns blue litmus paper red.

Let us analyze the chemical and physical properties of ethanol (${\text{C}}_2{\text{H}}_5\text{OH}$) to identify which statement is incorrect:

1. Physical Appearance and Odour: Ethanol is a clear, colourless liquid at room temperature and possesses a distinct, pleasant alcoholic smell. Therefore, this statement correctly describes ethanol.

2. Reaction with Sodium: Ethanol reacts with active metals like sodium to produce sodium ethoxide and release hydrogen gas according to the equation:

$2{\text{C}}_2{\text{H}}_5\text{OH}+2\text{Na}\to 2{\text{C}}_2{\text{H}}_5\text{ONa}+{\text{H}}_2\uparrow$

Therefore, this statement correctly describes ethanol.

3. Solubility in Water: Ethanol is a polar organic molecule capable of forming hydrogen bonds with water molecules. Consequently, it is completely miscible (soluble) in water in all proportions. This statement correctly describes ethanol.

4. Action on Litmus Paper: Ethanol is a neutral organic compound. It does not dissociate in aqueous solution to yield a significant concentration of hydrogen ions (${\text{H}}^{+}$). Hence, it has no effect on litmus paper and does NOT turn blue litmus paper red (which is a property of acidic substances like carboxylic acids).

Thus, the statement "It turns blue litmus paper red" does NOT describe a property of ethanol.