Question

A solution of iron(III) nitrate, Fe(NO3)3, was mixed with a solution of potassium carbonate, K2CO3. A precipitate was formed. What is the chemical formula of the precipitate?

Answer 1

Chemical formula of the precipitate is Fe(OH)₃

Step-by-step explanation:

Fe(NO₃)₃ and K₂CO₃ are strong electrolytes and completely dissociates in water. Carbonate ions is a weak base and combines with water to form hydroxide ions (OH⁻), as follows

CO₃²⁻ + H₂O <----------------> HCO₃⁻ + OH⁻

Ferric, Fe (III), combines with these hydroxide ions to form insoluble precipitates. Fe(OH)₃ is only partially soluble i.e., it does not completely dissociate in water. When the solutions of Fe(NO₃)₃ and K₂CO₃ are mixed together, Fe(OH)₃ precipitates out due to the strong electrostatic attraction between Fe (III) and hydroxide ions.