Chemistry-Functional Group Tests

NEET Chemistry Functional Group Tests MCQ Question

Type: MCQ-conceptual-Hard-Class 12

Which combination of statements correctly describes the functional group tests for copper ion (Cu 2+)?

A

Copper sulphide dissolves in nitric acid, forming a blue solution due to copper nitrate. Basic copper sulphate precipitates with ammonium hydroxide.

B

The blue solution turns purple when acidified with acetic acid. Tetraamminecopper(II) complex is formed in the presence of ammonium hydroxide.

C

Copper ions produce a yellow precipitate with potassium nitrite after treatment with aqua regia. The precipitate is identified as potassium hexanitritocobaltate(III).

D

Copper sulphide reacts with hydrochloric acid to form copper chloride, which precipitates as copper hydroxide when treated with ammonia.

Correct Answer

Option A

Detailed Explanation

Copper sulphide dissolves in nitric acid to yield copper nitrate, which gives a blue solution due to the formation of copper(II) ions. Ammonium hydroxide leads to the precipitation of basic copper sulphate, confirming the presence of Cu 2+ ions.

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