Attempt any five of the following:
(a) $\mathrm{Ce}(\mathrm{III})$ is easily oxidised to $\mathrm{Ce}(\mathrm{IV})$. Comment.
(b) $\mathrm{E}^{\circ}\left(\mathrm{Mn}^{2+} / \mathrm{Mn}\right)$ is -1.18 V . Why is this value highly negative in comparison to neighbouring $d$ block elements?
(c) Which element of $3 d$ series has lowest enthalpy of atomisation and why?
(d) What happens when sodium chromate is acidified?
(e) $\mathrm{Zn}, \mathrm{Cd}$ and Hg are soft metals. Why?
(f) Why is permanganate titration not carried out in the presence of HCl ?
(g) The lower oxides of transition metals are basic whereas the highest are amphoteric/acidic. Give reason.
(a) (i) Ishan's automobile radiator is filled with 1.0 kg of water. How many grams of ethylene glycol (Molar mass $=62 \mathrm{~g} \mathrm{~mol}^{-1}$ ) must Ishan add to get the freezing point of the solution lowered to $-2.8^{\circ} \mathrm{C}$. $\mathrm{K}_{\mathrm{f}}$ for water is $1.86{\mathrm{~K} \mathrm{~kg} . \mathrm{mol}^{-1} \text {. }}$
(ii) What type of deviation from Raoult's law is shown by ethanol and acetone mixture? Give reason.
OR
(b) (i) Boiling point of water at 750 mm Hg pressure is $99.68{ }^{\circ} \mathrm{C}$. How much sucrose (Molar mass $=342 \mathrm{~g} \mathrm{~mol}^{-1}$ ) is to be added to 500 g of water such that it boils at $100{ }^{\circ} \mathrm{C}$ ? $\left(\mathrm{K}_b\right.$ for water $=$ $0.52 \mathrm{~K} \mathrm{~kg} \mathrm{~mol}^{-1}$ ).
(ii) State Henry's law and write its any one application.
(a) An organic compound (A) with the molecular formula $\mathrm{C}_9 \mathrm{H}_{10} \mathrm{O}$ forms 2, 4-DNP derivative, reduces Fehling solution and undergoes Cannizzaro reaction. On vigorous oxidation, it gives 1, 2-benzene dicarboxylic acid.
(i) Identify the compound (A) and write its IUPAC name.
(ii) Write the reaction of compound (A) with
(1) 2,4-Dinitrophenyl hydrazine and
(2) Fehling solution
(iii) Write the equation of compound (A) when it undergoes Cannizzaro reaction.
OR
(b) (i) Account for the following:
(1) The alpha ( $\alpha$ )-hydrogens of aldehydes and ketones are acidic in nature.
(2) Oxidation of aldehydes is easier than ketones.
(ii) Arrange the following in :
(1) Decreasing reactivity towards nucleophilic addition reaction propanal, acetone, benzaldehyde.
(2) Increasing order of boiling point: Propane, Ethanol, Dimethylether, Propanal
(iii) Give simple chemical test to distinguish between Benzoic acid and Benzaldehyde.