Question 5

Q5 Excess zinc carbonate is added to hydrochloric acid in the preparation of zinc chloride salt. (i) Write an ionic equation for the reaction. (ii)  Why excess zinc carbonate is used? (iii) Briefly explain how the zinc chloride crystals can be obtained.

i) Normal Equation: ZnCO3(s) + 2H⁺Cl⁻ (aq) ---> Zn²⁺Cl⁻2 (aq) + H2O (L) + CO2 (g)
Ionic Equation: ZnCO3(s) + 2H⁺(aq) ---> Zn²⁺(aq)  H2O (L) + CO2 (g)


ii) Excess Zinc Carbonate will ensure that the hydrochloric acid is completely reacted.


iii) After adding Zinc Carbonate to hydrochloric acid until excess zinc carbonate is seen. we then filter these excess zinc carbonate out using a filter funnel and at the same time transfer the solution( ZnCl2) to a beaker. Evaporated the solution to remove water till its a saturated solution. When cooled the zinc chloride crystals will formed and can be obtained.