Question

$X$ g of calcium carbonate was completely burnt in air. The weight of the solid residue formed is $28$ g. What is the value of $X$ (in g)?

• A. $44$
• B. $200$
• C. $150$
• D. $50$

Answer 1

The correct option is D $50$

The balanced chemical equation is $CaC{O}_3\to CaO+C{O}_2$.

1 mole (100 g) of calcium carbonate on combustion produces 1 mol (56 g) of calcium oxide.

Thus, 28 g (0.5 mol) of calcium oxide will be produced by the combustion of 0.5 mol (50 g) of calcium carbonate.