Question

Which of the following ions will cause hardness in water

sample?

• A. $Ca^{2 +}$
• B. $Na^{+}$
• C. $Cl^{-}$
• D. $K^{+}$

Answer 1

Answer: (A)

$Ca^{2 +}$

Answer 2

: Presence of calcium and magnesium salts in the form of hydrogenarbonate, chloride and sulphate in water makes water ‘hard’.