Which compound does not form a precipitate when reacted with sodium hydroxide?

Fe (NO3) 3

Cu (NO3) 2

NaNO3

FeSO4

NaNO₃

Explanation:

A precipitate is a compound or a salt formed from a precipitation reaction and does not dissolve in water and therefore will exist in solid state.

From the choices given precipitation reaction will occur between;

Fe (NO₃) ₃ (aq) + 3NaOH (aq) → Fe (OH) ₃ (s) + 3NaNO₃ (aq) Cu (NO₃) ₂ (aq) + 2NaOH (aq) → Cu (OH) ₂ (s) + 2NaNO₃ (aq) FeSO₄ (aq) + 2NaOH (aq) → Fe (OH) ₂ (s) + Na₂SO₄ (aq)

Fe (OH) ₃, Cu (OH) ₂, and Fe (OH) ₂ are precipitates.

From the rules of solubility, hydroxides are insoluble except Ca (OH) ₂ which is slightly soluble and hydroxides of ammonium and alkali metals.