Which observation correctly distinguishes iron(II) ions from iron(III) ions when sodium hydroxide solution is added?

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Question

Which observation correctly distinguishes iron(II) ions from iron(III) ions when sodium hydroxide solution is added?

Accepted Answer

A. Iron(II) gives a green precipitate; iron(III) gives a reddish-brown precipitate — Iron(II) hydroxide is green and iron(III) hydroxide is reddish-brown, so adding NaOH solution distinguishes these two ions clearly. Students often confuse which colour corresponds to which oxidation state.

Answer

C. Iron(II) gives a white precipitate; iron(III) gives a blue precipitate

Answer

A. Iron(II) gives a green precipitate; iron(III) gives a reddish-brown precipitate

Answer

D. Iron(II) gives a reddish-brown precipitate; iron(III) gives a green precipitate

Answer

B. Iron(II) gives a blue precipitate; iron(III) gives a green precipitate

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