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Question Question 4(2020)
Distinguish between the following pairs of compounds using a reagent as a chemical test:
(i) Calcium nitrate and Zinc nitrate solution
(ii) Magnesium chloride and Magnesium nitrate solution
(i) When NaOH is added to the given soln., Zinc nitrate [Zn(NO3)2] reacts to form a gelatinous white ppt. which dissolves in excess of NaOH whereas, Ca(NO3)2 forms a milky white ppt. which is insoluble in excess of NaOH. Hence, the two can be distinguished.
(ii) Add silver nitrate soln. to the given solns., Magnesium chloride reacts to form a white ppt. which is soluble in NH4OH and insoluble in dil. HNO3. The other solution is Magnesium nitrate.
MgCl2 + 2AgNO3 ⟶ 2AgCl ↓ [white ppt.] + Mg(NO3)2
Mg(NO3)2 + AgNO3 ⟶ no white ppt.