Chemistry - Salt Analysis Question with Solution | TestHub
List - I Salts | List - II Characteristics |
|---|---|
(P) | (1) Residue obtained on strong heating of solid salt may change colour on exposure to heat |
(Q) | (2) On heating solid salt, a gas with specific odour can be obtained |
(R) | (3) Cation shows colour in Borax Bead test |
(S) | (4) Soluble salt of cation can give ppt. with in slightly alkaline medium |
| (5) Cation shows colour in flame test |
Options:
Answer:
Solution:
ZnCO₃ (P) matches with 1 and 4: It decomposes upon strong heating to form ZnO, which changes color from yellow (hot) to white (cold), and Zn²⁺ precipitates as a sulfide in a slightly alkaline medium (Group IV).
PbSO₄ (Q) matches with 1, 4, and 5: It decomposes at high temperatures yielding a lead oxide residue that shifts color upon cooling, can precipitate with H₂S, and exhibits a characteristic grayish/blue-white color in a flame test.
FeSO₄·7H₂O (R) matches with 2 and 4: Heating this green vitriol releases SO₂ and SO₃ gases, which have a pungent, suffocating odor, and iron cations show a distinct color in the Borax Bead test.
CaSO₄·2H₂O (S) matches with 5: Gypsum contains calcium (Ca²⁺) cations, which produce a distinct brick-red color during a flame test.
