A student breathes into limewater and observes it turns milky. What does this indicate, and what is the chemical responsible?

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Question

A student breathes into limewater and observes it turns milky. What does this indicate, and what is the chemical responsible?

Accepted Answer

B. Presence of carbon dioxide; it reacts with calcium hydroxide — Limewater (calcium hydroxide solution) turns milky in the presence of carbon dioxide, producing insoluble calcium carbonate as a precipitate. This is a standard biochemical test for carbon dioxide and demonstrates that the gas is produced during cellular respiration.

Answer

B. Presence of carbon dioxide; it reacts with calcium hydroxide

Answer

D. Presence of nitrogen; it displaces oxygen from the solution

Answer

C. Presence of water vapour; it condenses in the limewater

Answer

A. Presence of oxygen; it reacts with calcium hydroxide

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