Question

Match list I with list II and select the correct answer using the codes given below the lists.

	List - I		List - II
1.	Heavy water	A.	Bicarbonates of $Mg$ and $Ca$ in water
2.	Temporary hard water	B.	No foreign ions in water
3.	Soft water	C.	$D_{2}O$
4.	Permanent hard water	D.	Sulphates and chlorides of $Mg$ and $Ca$ in water

• A. 1 - C, 2 - D, 3 - B, 4 - A
• B. 1 - B, 2 - A, 3 - C, 4 - D
• C. 1 - B, 2 - D, 3 - C, 4 - A
• D. 1 - C, 2 - A, 3 - B, 4 - D

Answer 1

The correct option is D 1 - C, 2 - A, 3 - B, 4 - D

(1) Heavy water is deuterium oxide $\left(D_{2}O\right)$.

(2) Temporary hardness of water is due to the presence of bicarbonates of $Mg$ and $Ca$ in water. Thus, it is due to the presence of magnesium bicarbonate $KgHC{O}_3$ and calcium bicarbonate $CaHC{O}_3$.

(3) Soft water contains no foreign ions.

(4) The permanent hardness of water is due to sulphates and chlorides of $Mg$ and $Ca$ in water. Thus, it is due to the presence of calcium sulphate, magnesium sulphate, calcium chloride and magnesium chloride.