Which of the following will show the "Tyndall effect"?

Colloidal solution appears to be homogeneous but actually it is heterogeneous. Give justification for this statement.

When a bar magnet is brought closer to a mixture of iron filings and sulphur powder,iron particles stick to the magnet,whereas in the case of iron sulphide,no change is observed. When a mixture of iron and sulphur is added to carbon disulphide,sulphur dissolves,whereas in the case of iron sulphide,no change is observed. Justify the statement that the properties of a compound are different from its constituents,while a mixture shows the properties of its constituent elements using the example of iron and sulphur.

Calculate the mass of sodium sulphate required to prepare its $20\%$ (mass percent) solution in $100\,g$ of water. (in $,g$)

Calculate the mass of water and mass of glucose required to make $250 \, g$ of $40 \%$ solution of glucose.

How can we obtain different gases from air?