Answer to Question #96824 in General Chemistry for Alf kutta

Question

What happened when blue litmus paper is lowered into sour milk

Answer 1

Sour milk is an example of acid.The bacteria in milk combine it with oxygen to produce lactic acid. Like other acids, lactic acid has a sour taste.

Blue litmus paper turns red under acidic conditions and red litmus paper turns blue under basic or alkaline conditions.

Hence sour milk will turn blue litmus paper into red.