Identify oxidation number of Sulphur respectively in $\text{SO}_2$ and $\text{SO}_4^{2-}$ .

Identify colour change when NaCl solution is titrated against $\text{AgNO}_3$ solution using fluorescein indicator.

Which from the following metal chlorides does not contain water of crystallisation ?

What is the name of second lower homologue of $\text{CH}_3(\text{CH}_2)_2\text{COOH}$ ?