A piece of metal (M) is dissolved in nitric acid and the resulting solution is treated with a small quantity of sodium hydroxide to produce a white precipitate (B) which redissolves on the addition of excess alkali. The precipitate (B)when ignited in a crucible produces the oxide of the metal(m). The METAL M is
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Correct Answer: Option A
Explanation:
The correct answer is A: Zn (Zinc).
Here’s why:
1. Reaction with nitric acid:
When a metal (M) reacts with nitric acid, it forms a solution containing the metal ions. In this case, the resulting solution is treated with sodium hydroxide (NaOH), which typically forms a white precipitate of metal hydroxide. This suggests that the metal (M) forms a metal hydroxide that is insoluble in water but can dissolve in excess sodium hydroxide to form a soluble complex.
2. White precipitate (B):
The white precipitate (B) that redissolves in excess alkali is characteristic of zinc hydroxide (Zn(OH)₂). Zinc hydroxide is insoluble in water, but it dissolves in excess alkali to form a soluble complex like [Zn(OH)₄]²⁻.
3. Ignition of precipitate:
When the precipitate is ignited, it forms the oxide of the metal (ZnO). Zinc hydroxide decomposes upon heating to form zinc oxide.
Thus, the metal (M) is zinc (Zn), which is consistent with all the observations in the problem.
Therefore, the correct answer is A: Zn.
The correct answer is A: Zn (Zinc).
Here’s why:
1. Reaction with nitric acid:
When a metal (M) reacts with nitric acid, it forms a solution containing the metal ions. In this case, the resulting solution is treated with sodium hydroxide (NaOH), which typically forms a white precipitate of metal hydroxide. This suggests that the metal (M) forms a metal hydroxide that is insoluble in water but can dissolve in excess sodium hydroxide to form a soluble complex.
2. White precipitate (B):
The white precipitate (B) that redissolves in excess alkali is characteristic of zinc hydroxide (Zn(OH)₂). Zinc hydroxide is insoluble in water, but it dissolves in excess alkali to form a soluble complex like [Zn(OH)₄]²⁻.
3. Ignition of precipitate:
When the precipitate is ignited, it forms the oxide of the metal (ZnO). Zinc hydroxide decomposes upon heating to form zinc oxide.
Thus, the metal (M) is zinc (Zn), which is consistent with all the observations in the problem.
Therefore, the correct answer is A: Zn.