When milk turns sour, in which direction does its pH change?
Answer and explanation
Correct answer: pH decreases
When milk turns sour, microorganisms convert lactose into lactic acid through fermentation. The increased acid concentration raises hydrogen-ion concentration, so the pH decreases. Therefore option A is correct. A rise in pH would indicate a movement toward basicity, not sourness. The pH does not become fixed at 14, and it cannot remain unchanged when an acidic product is being formed.
Frequently asked questions
What is the correct answer to this question?
pH decreases
Why is this the correct answer?
When milk turns sour, microorganisms convert lactose into lactic acid through fermentation. The increased acid concentration raises hydrogen-ion concentration, so the pH decreases. Therefore option A is correct. A rise in pH would indicate a movement toward basicity, not sourness. The pH does not become fixed at 14, and it cannot remain unchanged when an acidic product is being formed.
Which subject and chapter does this question cover?
This is a Class 10 Science question. Chapter: Chemical Substances – Nature and Behaviour. Topic: Acids, Bases, and Salts.
