The substances that sublime easily are

State the principle involved in separating a mixture containing kerosene and water.

Iron filings and sulphur were mixed together and divided into two parts,$A$ and $B$. Part $A$ was heated strongly while Part $B$ was not heated. Dilute hydrochloric acid was added to both the parts and evolution of gas was seen in both the cases. How will you identify the gases evolved?

Suggest separation technique$(s)$ one would need to employ to separate the following mixtures:
$(a)$ Mercury and water
$(b)$ Potassium chloride and ammonium chloride
$(c)$ Common salt,water and sand
$(d)$ Kerosene oil,water and salt

Crystallisation is a better technique than simple evaporation. Give one reason to justify the statement.

Enumerate any two differences between simple distillation and fractional distillation.