JEE Main 2022 · 30 Jul · Shift 2 · Chemistry Q37

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ChemistrySingle correct+4 / -1Question 37 of 90

The hardness of water is generally expressed in terms of CaCO $_3$ equivalent. The possible reasons are as follows:

(A) Its molar mass is 100, so the calculations become easier.

(B) It decomposes at a temperature, 1200 K.

(D) It is moisture insensitive.

Choose correct option from the following for the reasons.

(A) and (B) only

(A) and (D) only

(B) and (D) only

(A), (B), and (C) only

Answer and worked solution

Official answer: D

Reasons. CaCO₃ has molar mass 100, which makes conversion easy; it is the common insoluble precipitate in hard water; and it is a stable compound that decomposes only on strong heating. The key takes (A), (B) and (C).

(D)

Topics:Water and hydrogen peroxide

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JEE Main 2022 · 30 Jul · Shift 2, Chemistry question 37