Question

When calcium carbonate is heated, it decomposes to give __________.
This question has multiple correct options.
(A). Water
(B). Calcium oxide
(C). Carbon dioxide
(D). None of these

Answer 1

Calcium carbonate is also known as limestone. It is also a dietary supplement and is used when the calcium intake is not enough. When calcium carbonate is heated in a test tube, it involves a colourless and an odourless gas and also a white precipitate.

Complete step by step answer:
Calcium carbonate is a substance found in rocks such as minerals calcite and aragonite. It is a chemical compound with the chemical formula $CaC{O_3}$ .
It is the main component of pearls and the shells of marine organisms, snails and even eggs. It is also an active ingredient in agricultural lime and is generally created when calcium ions in hard water react with carbonate ions to create lime scale. Calcium carbonate also has medicinal uses. It is used as a calcium supplement or as an antacid but its excessive consumption can be hazardous and can cause poor digestion.
The chemical properties of calcium carbonate includes the reaction of $CaC{O_3}$ with an acid and the thermal decomposition of calcium carbonate.
(A). When $CaC{O_3}$ reacts with an acid to produce carbon dioxide. The reaction equation is:
$CaC{O_3}\left( s \right) + 2{H^ + }\left( {aq} \right) \to C{a^{2 + }}\left( {aq} \right) + C{O_2}\left( g \right) + {H_2}O\left( g \right)$
(B). When $CaC{O_3}$ is heated, it releases carbon dioxide $C{O_2}$ known as thermal decomposition or also calcination.
The reaction equation is:
$CaC{O_3}\left( s \right) \to CaO\left( s \right) + C{O_2}\left( g \right)$ .
When $CaC{O_3}$ is heated, the calcium oxide called quicklime and carbon dioxide as a gaseous product is formed.
Hence, when $CaC{O_3}$ is heated it decomposes to give calcium oxide and carbon dioxide.

So, the correct answer is Option B,C .

Note: $CaC{O_3}$ also reacts with water and with $C{O_2}$ to form calcium bicarbonate
The reaction involved is:
$CaC{O_3}\left( s \right) + C{O_2}\left( g \right) + {H_2}O\left( l \right) \to Ca{\left( {HC{O_3}} \right)_2}\left( {aq} \right)$
This reaction is important in the erosion of carbonate rock and ions that even lead to hard water.