To make a saturated solution, 36 g of sodium chloride is dissolved in 100 g of water at 293 K. Find its concentration at this temperature.

Classify the following as chemical or physical changes:

1. Cutting of trees
2. Melting of butter in a pan
3. Rusting of almirah
4. Boiling of water to form steam
5. Passing of electric current through water and the water breaking down into hydrogen and oxygen gases.
6. Dissolving common salt in water
7. Making a fruit salad with raw fruits, and
8. Burning of paper and wood

Which separation techniques will you apply for the separation of the following?

(a) Sodium chloride from its solution in water.

(b) Ammonium chloride from a mixture containing sodium chloride and ammonium chloride.

(c) Small pieces of metal in the engine oil of a car.

(d) Different pigments from an extract of flower petals.

(e) Butter from curd.

(f) Oil from water.

(g) Tea leaves from tea.

(h) Iron pins from sand.

(i) Wheat grains from husk.

(j) Fine mud particles suspended in water.

Write the steps you would use for making tea. Use the words solution, solvent, solute, dissolve, soluble, insoluble, filtrate, and residue.