Iron(II) ions with sodium hydroxide produce which precipitate?

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Multiple Choice

Iron(II) ions with sodium hydroxide produce which precipitate?

Explanation:
When a base like sodium hydroxide is added to iron(II) ions, the hydroxide ions meet the iron(II) ions to form iron(II) hydroxide, Fe(OH)2. This compound is not soluble in water, so it appears as a solid precipitate. Its characteristic pale green color comes from iron in the +2 oxidation state. The key idea is that Fe2+ reacts with OH− to form an insoluble hydroxide that reflects the green color. If left in air, Fe(OH)2 can slowly oxidize to Fe(OH)3, which is brown, so you might see a color change over time. This explanation matches the observation of a green precipitate that does not dissolve in excess base.

When a base like sodium hydroxide is added to iron(II) ions, the hydroxide ions meet the iron(II) ions to form iron(II) hydroxide, Fe(OH)2. This compound is not soluble in water, so it appears as a solid precipitate. Its characteristic pale green color comes from iron in the +2 oxidation state. The key idea is that Fe2+ reacts with OH− to form an insoluble hydroxide that reflects the green color.

If left in air, Fe(OH)2 can slowly oxidize to Fe(OH)3, which is brown, so you might see a color change over time. This explanation matches the observation of a green precipitate that does not dissolve in excess base.

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