Question

The drying agent which absorbs carbon dioxide and reacts violently with water is:
(A) Sodium carbonate
(B) Alcohol
(C) Concentrated ${H_2}S{O_4}$
(D) Calcium oxide

Answer 1

Drying agents are anhydrous inorganic salts which acquire hydration when exposed to wet solution or to moist air. the most common drying agents such as sodium sulfate or magnesium sulfate, the crystals form lumps when they absorb water.

Complete step by step answer:
Let us discuss all the given compound i.e. sodium carbonate, Alcohol, concentrated ${H_2}S{O_4}$ and calcium oxide.
A). Sodium carbonate: Sodium carbonated is an inorganic compound with the formula $N{a_2}C{O_3}$. It exists as white salt and is soluble in water. It yields moderately alkaline solution when dissolved in water. The sodium carbonate is used in the manufacture of soap, detergent glass and paper etc. $N{a_2}C{O_3}$ is also used in the softening of hard water. Sodium carbonate is also a food additive and used in cooking.
B). Alcohol: Alcohol which is known as ethanol and has chemical formula ${C_2}{H_5}OH.$ The alcoholic drinks such as beer, whiskey, wine etc. Alcohol decreases anxiety, produces a mood life and increases confidence. Alcohol has a variety of side effects. It can damage the liver, brain etc. leading to a death of a person.
C). Concentrated ${H_2}S{O_4}$: Concentrated ${H_2}S{O_4}$ or concentrated sulphuric acid as a very strong acid. It is a colourless, odourless and viscous liquid. It is soluble in water but solubility of it in water is an exothermic process. Upon coming in direct contact with concentrated ${H_2}S{O_4}$ can cause severe chemical burns on the skin.
D). Calcium acid: Calcium acid commonly known as quickly line is a chemical compound with chemical formula $CaO.$ It is white powder and produces an alkaline solution when dissolved in water. Calcium acid is the main ingredient in the manufacture of cement. It is also used in preparation of paper and plaster.
The drying reagent means that the substance should absorb water. The drying reagent which absorbs carbon dioxide and reacts violently with water is calcium oxide.
Hence option (D) is the correct answer.
$CaO + {H_2}O \to Ca{(OH)_2}$ [Calcium hydroxide]
$CaO + C{O_2} \to CaC{O_3}$ [Calcium Carbonate]

Note: The reaction of $CaO$ and water is extremely exothermic. A less amount of energy can be utilized for carrying out other reactions. Precautions should be taken before reacting these two substances.