Question

On adding dilute HCl to the chalk piece, $CO_2$ is evolved. This is an example of:
A.Heterogeneous reaction
B.Acid base reaction
C.Oxidation Reduction Reaction
D.Catalysed reaction

Answer 1

Hint: The chemical compound calcium carbonate (Chalk) has the formula $CaCO_3$. It's a natural rock found all over the world, and it's the main component of marine organisms' shells, snail shells, and eggshells. At room temperature and humidity, hydrogen chloride (HCl) is a gas made up of the components hydrogen and chlorine. Hydrochloric acid is the name for a gas solution of water.

Complete answer:
Calcium carbonate is calcium's carbonic salt ($CaCO_3$). Calcium carbonate is used as a phosphate buffer in hemodialysis, as an antacid for immediate relief of indigestion and heartburn in gastric hyperacidity, and as a calcium supplement to avoid and cure osteoporosis.
Hydrochloric acid, also known as muriatic acid, is a hydrogen chloride aqueous solution. It's a colourless liquid with a heavy, pungent odour. It's considered a heavy acid. In the digestive processes of most animal species, including humans, it is a part of gastric acid. Hydrochloric acid is a popular laboratory reagent and chemical used in industry.
A heterogeneous mixture is one in which the composition varies from one part to the next. Two or more phases make up a heterogeneous mixture. When oil and water are mixed together, they form two distinct layers rather than mixing equally. Each layer is referred to as a phase.
\[2HCl(l) + CaC{O_3}(s) \to CaOC{l_2}(s) + C{O_2}(g)\]
$CaOCl_2$ is the molecular formula for calcium hypochlorite, an inorganic chemical compound. They're also known as calcium oxychloride, and $CaOCl_2$ is also known as bleaching or chlorine powder.
Carbon dioxide ($CO_2$) is an acidic, colourless gas with a density that is around $53\%$ greater than that of dry air. A carbon atom is covalently double bonded to two oxygen atoms in a carbon dioxide molecule. It is found as a trace gas in the Earth's atmosphere.
Hence the correct answer is option A.

Note:
The inorganic compound calcium hypochlorite has the formula $Ca(OCl)_2$. It is the primary active ingredient in industrial bleaching concentrate, chlorine powder, or chlorinated lime products that are used for water treatment and bleaching. This compound is more soluble than sodium hypochlorite and has more available chlorine (liquid bleach). Although commercial samples look yellow, it is a white solid. Because of its sluggish decomposition in damp air, it has a heavy chlorine odour.