Question

Lithium arsenate (Li3AsO4) and iron nitrate (Fe(NO3)3) are dissolved in water. What precipitate would you expect to form? what is the name and formula?

Answer 1

Answer:

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

• The chemical formula of the precipitate is Fe(OH)₃

Explanation:

• Fe(NO₃)₃ and K₂CO₃ are strong electrolytes and completely dissociate in water. Carbonate ions is a weak base and combine with water to form hydroxide ions (OH⁻), 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, Fe(OH)₃ precipitates out due to the strong electrostatic attraction between Fe (III) and hydroxide ions.