Write one point of difference between concentration and solubility.

Why is the interconversion of states of matter considered a physical change? Give three reasons to justify your answer.

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

What is distillation? List the two conditions essential for using this as a method of separation of components of a mixture.

Compare solution,suspension,and colloids in terms of:
$(a)$ stability
$(b)$ filterability
$(c)$ Tyndall effect

$(a)$ $7\, g$ of iron filings and $4\, g$ of sulphur powder is treated with dilute sulphuric acid at room temperature. Name the gas produced.
$(b)$ The same mixture is heated strongly,cooled and then treated with dilute sulphuric acid. Which gas would be produced?
$(c)$ What is the cause of this difference in results of chemical reaction in different conditions?