Name the equipment that can be used to warm the filtrate gently in Step 6.
How to approach this question
Step 6 requires gentle heating of a liquid to evaporate some of the water. What piece of laboratory equipment is specifically designed for evaporation? What heat source is commonly used? An alternative method involves heating with hot water.
Full Answer
Evaporating basin and Bunsen burner (with tripod and gauze). Or water bath.
To warm the filtrate gently and evaporate water to the point of crystallisation, an evaporating basin is used. It has a wide surface area which aids evaporation. This is typically placed on a tripod and gauze and heated from below by a Bunsen burner on a gentle flame. A safer and gentler method is to use a water bath, where the evaporating basin is placed over a beaker of gently boiling water. This provides indirect, even heating and prevents the solution from boiling too vigorously.
Common mistakes
✗ Just "Bunsen burner" - this is not gentle heating on its own.
✗ "Beaker" - while you can heat a beaker, an evaporating basin is the correct piece of equipment for this specific task.
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