This question is about making a soluble salt. Plan a method to make pure, dry crystals of zinc chloride from zinc carbonate and a dilute acid.

To make a soluble salt from an insoluble reactant, the following four-stage process is used:\n\n1. **Reaction:** The correct acid is needed to provide the chloride part of the salt, so **hydrochloric acid (HCl)** is used. Zinc carbonate is an insoluble solid. It is added to the acid until no more reacts (the fizzing stops) and there is solid left over. This is called adding in **excess** and ensures all the acid is neutralised. The reaction is: ZnCO₃(s) + 2HCl(aq) → ZnCl₂(aq) + H₂O(l) + CO₂(g).\n\n2. **Filtration:** The excess (unreacted) zinc carbonate must be removed from the zinc chloride solution. This is done by **filtration**. The zinc chloride solution passes through the filter paper as the **filtrate**.\n\n3. **Crystallisation:** To get solid crystals from the solution, most of the water must be removed. The filtrate is gently heated in an evaporating basin to evaporate about half the water, creating a saturated solution. This solution is then left to cool slowly. As it cools, the solubility of the zinc chloride decreases, and pure crystals form.\n\n4. **Drying:** The crystals are separated from the remaining liquid (e.g., by decanting or filtering) and then dried, for example, by patting with filter paper or in a low-temperature oven.