Draw the structures of chromate and dichromate ions.

Give reasons:

(a) d- block elements exhibit more oxidation states than f-block elements.

(b) Orange solution of potassium dichromate turns yellow on adding sodium hydroxide to it.

(c) Zirconium (Z= 40) and Hafnium (Z = 72) have almost similar atomic radii.

Describe the preparation of potassium permanganate from pyrolusite ore. Write balanced chemical equation for one reaction to show the oxidizing nature of potassium permanganate.

A ketone A which undergoes haloform reaction gives compound B on reduction. B on heating with sulphuric acid gives compound C, which forms mono-ozonide D. The compound D on hydrolysis in presence of zinc dust gives only acetaldehyde. Write the structures and IUPAC names of A, B and C. Write down the reactions involved.

Predict the products formed when cyclohexanecarbaldehyde reacts with following reagents.

(a) PhMgBr and then H₃O⁺.

(b) Tollens’ reagent.