Chemistry
Give a chemical test to distinguish between:
(a) dilute sulphuric acid and dilute hydrochloric acid (using lead nitrate solution).
(b) dilute sulphuric acid and concentrated sulphuric acid.
(c) Dilute sulphuric acid and dilute hydrochloric acid [using barium chloride solution]
Answer
(a) When dil sulphuric acid is reacted with lead nitrate it produces a white ppt. of lead sulphate which remains insoluble even on heating.
Pb(NO3)2 + H2SO4 (dil) ⟶ 2HNO3 + PbSO4 ↓ [white ppt. formed]
When dil hydrochloric acid is reacted with lead nitrate, a white ppt. of lead chloride is formed which dissolves on heating.
Pb(NO3)2 + 2HCl ⟶ 2HNO3 + PbCl2 ↓ [white ppt. formed]
(b) Dilute sulphuric acid when reacted with zinc produces Hydrogen gas which burns with a pop sound.
Zn + H2SO4 [dil.] ⟶ ZnSO4 + H2 ↑
Concentrated sulphuric acid when reacted with zinc produces SO2 gas which turns acidified potassium dichromate paper green.
Zn + 2H2SO4 [conc.] ⟶ ZnSO4 + 2H2O + SO2 ↑
(c) Barium chloride soln. reacts with dilute sulphuric acid to give a white ppt. of barium sulphate (BaSO4) but with dilute hydrochloric acid no white ppt. is produced since barium chloride is soluble in dil. sulphuric acid.
H2SO4 (dil.) + BaCl2 (aq.) ⟶ 2HCl + BaSO4 ↓ [white ppt. formed]
HCl (dil.) + BaCl2 (aq.) ⟶ No reaction
Related Questions
Dilute and concentrated sulphuric acid can be distinguished by using metals copper and zinc. Explain by giving balanced equations.
Give two balanced reactions of each type to show the following properties of sulphuric acid:
(a) Acidic nature
(b) Oxidising agent
(c) Dehydrating Nature
(d) Non-volatile nature
State the conditions required for the conversion of sulphur dioxide to sulphur trioxide to take place:
Making use only of substances given: dil. sulphuric acid, Sodium carbonate, Zinc, Sodium Sulphite, Lead, Calcium carbonate:
Give equations for the reactions by which you could obtain:
(i) hydrogen
(ii) sulphur dioxide
(iii) carbon dioxide
(iv) zinc carbonate (2 steps)