(a) Which of the following species cannot act as a ligand? Give reason.

$$\mathrm{OH}^{-}, \mathrm{NH}_4^{+}, \mathrm{CH}_3 \mathrm{NH}_2, \mathrm{H}_2 \mathrm{O}$$

(b) The complex $$\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_5\left(\mathrm{NO}_2\right)\right] \mathrm{Cl}_2$$ is red in colour. Give IUPAC name of its linkage isomer.

Why is boiling point of o-dichlorobenzene higher than p-dichlorobenzene but melting point of para isomer is higher than ortho isomer?

For the pair phenol and cyclohexanol, answer the following

(a) Why is phenol more acidic than cyclohexanol?

(b) Give one chemical test to distinguish between the two.

(a) (i) Draw the zwitter ion structure for sulphanilic acid.

(ii) How can the activating effect of $$-\mathrm{NH}_2$$ group in aniline be controlled?

OR

(b) (i) Complete the reaction with the main product formed:

(ii) Convert Bromoethane to Propanamine.