The right option for the mass of CO_2 produced by heating 20 g of 20% pure limestone is (Atomic mass of Ca = 40)CaCO_3 1200\ K CaO + CO_2

1. 1.32 g

2. 1.12 g

3. 1.76 g

4. 2.64 g

Doubtly Asked 30 Oct 2026 NEET UG 2023 Practice test neet Save WhatsApp Report

1 answer

Best answer

Answer: 3. 1.76 g

Key idea: Only the pure \(\mathrm{CaCO_3}\) decomposes; find its moles and use 1:1 mole ratio with \(\mathrm{CO_2}\).

Pure \(\mathrm{CaCO_3} = 20 \times \frac{20}{100} = 4\) g. Molar mass = 40 + 12 + 48 = 100 g/mol.

Moles = 4/100 = 0.04 mol. \(\mathrm{CaCO_3 \rightarrow CaO + CO_2}\) gives 0.04 mol \(\mathrm{CO_2}\).

Mass of \(\mathrm{CO_2} = 0.04 \times 44 = 1.76\) g. Option 3.

Doubtly AI · 30 Oct 2026 AI-generated · not yet verified Report

Was this answer helpful?