A student tests an unknown solution and finds that adding sodium hydroxide solution produces a blue precipitate. Which ion is most likely present in the solution?

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Question

A student tests an unknown solution and finds that adding sodium hydroxide solution produces a blue precipitate. Which ion is most likely present in the solution?

Accepted Answer

C: Cu²⁺ — Cu²⁺ ions react with hydroxide ions to form copper(II) hydroxide, which is a blue precipitate. Fe²⁺ ions form a green precipitate, Fe³⁺ ions form a red-brown precipitate, and Zn²⁺ ions form a white precipitate with sodium hydroxide solution.

Answer

A: Fe²⁺

Answer

B: Fe³⁺

Answer

C: Cu²⁺

Answer

D: Zn²⁺

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