Neco 2022 Chemistry Question 15

5.00 g of a pure secondary alcohol with molecular formula \(\text{C}_5\text{H}_{12}\text{O}\) (M = 88 g·mol⁻¹) is oxidised with excess \(\text{K}_2\text{Cr}_2\text{O}_7^{2-}\) in acidic medium to give the corresponding ketone. The ketone is then reacted with 2,4‑dinitrophenylhydrazine (DNPH) to form the hydrazone, which is isolated and weighed. The isolated hydrazone mass is 6.20 g and its molecular formula is \(\text{C}_{11}\text{H}_{12}\text{N}_4\text{O}_5\) (M = 252 g·mol⁻¹). Assuming the oxidation step proceeds with 100 % yield and that the only loss of material occurs in the DNPH step, (i) state the IUPAC name of the alcohol (assuming a straight‑chain structure), and (ii) calculate the percentage yield of the DNPH reaction.