Chemistry - Mole Concept Question with Solution | TestHub
A metallic chloride, denoted as (A) reacts with NaOH in the presence of to yield a yellow - colored solution containing salt (B) On adding dilute , the solution turns orange due to the formation of compound (C).
When compound (D) is heated with (C) in the presence of concentrated H₂SO₄, a red, volatile compound (E) is generated. Compound (E), upon absorption in NaOH, regenerates a yellow solution of salt (B), which produces a yellow precipitate on treatment with acidified lead acetate solution.
Compound (C), when reacted with NH₄Cl, gives compound (F), which on heating decomposes into a green solid (G), water, and a colorless gas. Moreover, compound (D) imparts a golden-yellow flame color.
Identify the compounds (A) through (G) and calculate the total number of atoms per formula unit of A, B, C, D, E, F, G.
Answer:
Solution:
Identifications (A → G)
A = CrCl₃ (chromium (III) chloride) | 4 |
|---|---|
B = Na₂CrO₄ (chromate ion; yellow in basic medium) | 7 |
C = Na₂Cr₂O₇ (dichromate ion; orange in acidic medium) | 11 |
D = NaCl (sodium chloride - gives golden-yellow flame) | 2 |
E = CrO₂Cl₂ (chromyl chloride, red, volatile liquid) | 5 |
F = (NH₄)₂Cr₂O₇ (ammonium dichromate) | 19 |
G = Cr₂O₃ (chromium (III) oxide; green residue) | 5 |
| 53 |