Chemistry Problems

RH₂ (ion exchange resin) can replace Ca²⁺ in hard water as:

RH+ Ca²⁺ ® RCa + 2H⁺

1 liter of hard water passing through RH₂ has pH 2. Hence hardness in ppm of Ca²⁺ is:

(a) 200 (b) 100 (c) 50 (d) 125 Ans-a.

A solution contains Na₂CO₃ and NaHCO₃. 10 ml of the solution required 2.5 ml of 0.1 M H₂SO₄ for neutralization using phenolphthalein as indicator. Methyl orange is then added when a further 2.5 ml of 0.2 M H₂SO₄ was required. The amount of Na₂CO₃ and NaHCO₃ in 1 liter of the solution is:

(a) 5.3 g and 4.2 g (b) 3.3 g and 6.2 g (c) 4.2 g and 5.3 g (d) 6.2 g and 3.3 g

Ans----(a)