The diagram shows steps followed when carrying out a test on a green leaf: step 1 boil in water; step 2 boil in alcohol in a hot-water bath (burner off); step 3 rinse in cold water; step 4 add iodine on a white tile.

A student also separated a mixture of sodium chloride and sand by adding water and stirring; the sodium chloride dissolved.

1. aGive the reason for boiling the leaf in water in step 1. [1]
2. bGive the reason for boiling the leaf in alcohol in step 2. [1]
3. cGive the reason for switching off the Bunsen burner in step 2. [1]
4. dState the result for a positive test in step 4. [1]
5. eExplain the result. [1]
6. fComplete: sodium chloride dissolved in water to form a colourless ___; the sand did not dissolve because it is ___ in water; sodium chloride is a ___ in this experiment. [3]
7. gName two apparatus that could be used to separate sand from the mixture of water, sodium chloride and sand. [2]

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