Give a reason why carbon dioxide and sulphur dioxide cannot be distinguished by using lime water.

Salts A, B, C, D and E undergo reactions (i) to (v) respectively. Identify the anion present in each salt.

(i) When AgNO₃ solution is added to a soln. of A, a white precipitate, insoluble in dilute nitric acid, is formed.

(ii) Addition of dil. HCl to B produces a gas which turns lead acetate paper black.

(iii) When a freshly prepared solution of FeSO₄ is added to a soln. of C and conc. H₂SO₄ is gently poured from the side of the test-tube, a brown ring is formed.

(iv) When dil. H₂SO₄ is added to D a gas is produced which turns acidified K₂Cr₂O₇ soln. from orange to green.

(v) Addition of dil. HCl to E produced an effervescence. The gas produced turns limewater milky but does not effect acidified K₂Cr₂O₇ soln.

The salt which in solution gives a pale green ppt. with NaOH soln. and a white ppt. with barium chloride solution is :

1. Iron (III) sulphate
2. Iron (II) sulphate
3. Iron (II) chloride
4. Iron (III) chloride

CO₂ and SO₂ gas can be distinguished using :

1. moist blue litmus paper
2. lime water
3. acidified K₂Cr₂O₇ paper
4. none of the above.