Q: Carbon dioxide gas, when passed through lime water, brings about which of the following reactions?
(a)CaCO3 + H2O + CO2 → Ca(HCO3)2
(b)Ca(OH)2 + CO2 → CaCO3 + H2O
(c)CaO + CO2 → CaCO3
(d)CaCl2 + H2O + CO2 → CaCO3 + 2HCl
Correct Answer: (b)
The correct answer is (c): CaO + CO2 → CaCO3. Subject: Environment & Ecology | Sub-topic: Climate Change & Greenhouse Gases Note: This answer was determined through AI-based research. Verify against the official answer key when available.