Lime reacts exothermally with water to give 'A' which has low solubility in water. Aqueous solution of 'A' is often used for the test of $\mathrm{CO}_{2}$, a test in which insoluble B is formed. If B is further reacted with $\mathrm{CO}_{2}$ then soluble compound is formed 'A' is

JEE Main · 2023 · 10 Apr 2023 · Shift 1 · s-Block Elements

Lime reacts exothermally with water to give 'A' which has low solubility in water. Aqueous solution of 'A' is often used for the test of

CO_{2}

, a test in which insoluble B is formed. If B is further reacted with

CO_{2}

then soluble compound is formed 'A' is

(A)Quick lime
(B)Slaked lime✓ Correct
(C)Lime water
(D)White lime

Answer: (B)

Solution

Lime is calcium oxide, and its exothermic reaction with water, called slaking, gives calcium hydroxide, which is only sparingly soluble in water; this product is slaked lime. Its clear saturated solution is lime water, used to test for carbon dioxide: passing the gas in precipitates insoluble calcium carbonate, which turns the solution milky. On passing excess carbon dioxide the milkiness clears, because the carbonate is converted to soluble calcium hydrogencarbonate. The compound described as A is slaked lime.

JEE Main · 2023 · 10 Apr 2023 · Shift 1 · Single correct option

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JEE Main · 2023 · 10 Apr 2023 · Shift 1 · s-Block Elements

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