Hard and soft water - Jamb Chemistry Past Questions and Answers

Question 11:

• JAMB 2011

Hardness of water is mainly due to the presence of

A. Calcium hydroxide or magnesium hydroxide
B. Calcium trioxocarbonate (IV) or calcium tetraoxosulphate (VI)
C. Sodium hydroxide or magnesium hydroxide
D. Calcium chloride or sodium chloride salts

Question 12:

• JAMB 2012

The chemicals used to soften hard water involves the addition of

A. Insoluble sodium compounds which from soluble solutions of calcium and magesium
B. Solube soudium compounds which from soluble solutions of calcium and magnesium ions
C. Solube sodium compounds which from insoluble precipitates of calcium and magnesium ions
D. Insoluble precipitates of calcium and magnesium ions

Question 13:

• JAMB 2014

Water is said to be temporarily hard when it contains

A. Ca (HCO₃)₂ and Mg (HCO₃)₂ salts
B. Ca (HCO₃)₂ and CaCO₃ SALTS
C. Mg(HCO₃)₂ and CaSO₄ salts
D. CaSO₄ and Ca(HCO₃)₂ salts

Question 14:

• JAMB 2019

The two ions responsible for hardness in water are

A. Ca\(^{2+}\) and / or Mg\(^{2+}\)
B. K\(^+\) and / or Mg\(^{2+}\)
C. Ca\(^{2+}\) and / or Li\(^+\)
D. Ca\(^{2+}\) and / or Na\(^+\)