Question

(a) HCl, HNO₃ and H₂SO₄ are the formulae of three compounds. Which of these compounds has the highest boiling point and which has the lowest?
(b) Dilute hydrochloric acid and dilute sulphuric acid are both colourless solutions. How will the addition of barium chloride solution to each help to distinguish between the two?

Answer 1

(a) H₂SO₄ has the highest boiling point of 338⁰C and HCl has the lowest boiling point of $-$85⁰C.
(b) When barium chloride is added to sulphuric acid, sulphuric acid displaces the more volatile acid (hydrochloric acid) from it and gives a white precipitate of barium sulphate. On the other hand, barium chloride shows no reaction on being added to hydrochloric acid.

BaCl₂ + H₂SO₄ → BaSO₄↓ + 2HCl
BaCl₂ + HCl → No reaction