What is the action of litmus on ethanol ?

What is the action of litmus on ethanol ?

Litmus is neutral towards ethanol
Ethanol turns blue litmus to red; confirming acidic nature of ethanol
Ethanol turns red litmus to blue; confirming basic nature of ethanol
Ethanol decolorizes litmus through bleaching action
This question was previously asked in
UPSC NDA-2 – 2023
A) Litmus is neutral towards ethanol.
– Litmus is an acid-base indicator. It turns red in acidic solutions (pH < 7) and blue in basic solutions (pH > 7).
– Ethanol (C₂H₅OH) is an alcohol. The -OH group in alcohols is covalently bonded, unlike the ionic hydroxide in strong bases (e.g., NaOH).
– Alcohols are generally considered neutral compounds in aqueous solutions. While they can act as very weak acids (donating a proton from the -OH group, especially when reacting with strong bases like alkali metals) or very weak bases (accepting a proton from a strong acid at the oxygen atom), their acidity or basicity is negligible in the context of affecting litmus paper pH indicators.
– Ethanol does not dissociate significantly in water to produce H⁺ ions (acidic) or OH⁻ ions (basic).
– Therefore, when litmus paper is placed in ethanol or an aqueous solution of ethanol, its color remains unchanged (red litmus stays red, blue litmus stays blue), indicating a neutral pH.
– Ethanol does not possess bleaching properties like chlorine-based compounds.
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