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.
Answer
i) ZnCO3(S) + 2HCl(aq) ---> ZnCl2(aq) + H2O(L) + CO2(g)
ionic equation: ZnCO3(s) + 2H(+)(aq)---> Zn(2+)(aq) H2O(L) +CO2(g)
ii) to ensure that the hydrochloric acid is completely reacted.
iii) After the hydrochloric acid is comepletely reacted, filter the excess zinc carbonate, heat the filtrate till little amount is left for crystalization and lastly let it cool down and crystals will be form.