How would you confirm that a colorless liquid given to you is pure water?

How are sol,solution,and suspension different from each other?

Pragya tested the solubility of four different substances at different temperatures and collected the data as given below (results are given in the following table,as grams of substance dissolved in $100 \,g$ of water to form a saturated solution).

Substance Dissolved	$283 \,K$	$293 \,K$	$313 \,K$	$333 \,K$	$353 \,K$
Potassium nitrate	$21$	$32$	$62$	$106$	$167$
Sodium chloride	$36$	$36$	$36$	$37$	$37$
Potassium chloride	$35$	$35$	$40$	$46$	$54$
Ammonium chloride	$24$	$37$	$41$	$55$	$66$

$(a)$ What mass of potassium nitrate would be needed to produce a saturated solution of potassium nitrate in $50 \,g$ of water at $313 \,K$?
$(b)$ Pragya makes a saturated solution of potassium chloride in water at $353 \,K$ and leaves the solution to cool at room temperature. What would she observe as the solution cools? Explain.

Explain the following giving examples:
$(a)$ Saturated solution
$(b)$ Pure substance

Identify the solutions among the following mixtures:
$(a)$ Soil
$(b)$ Sea water
$(c)$ Air
$(d)$ Coal
$(e)$ Soda water

Which of the following are chemical changes?
$(a)$ Growth of a plant
$(b)$ Rusting of iron
$(c)$ Mixing of iron filings and sand
$(d)$ Cooking of food
$(e)$ Digestion of food
$(f)$ Freezing of water
$(g)$ Burning of a candle