JEE (Advanced) 2008 Paper-1
For the following questions answer them individually
Under the same reaction conditions, initial concentration of 1.386 mol dm$$^{-3}$$ of a substance becomes half in 40 seconds and 20 seconds through first order and zero order kinetics, respectively. Ratio $$\left(\frac{k_1}{k_0}\right)$$ of the rate constants for first order $$(k_1)$$ and zero order $$(k_0)$$ of the reactions is
2.5 mL of $$\frac{2}{5}$$ M weak monoacidic base $$(K_b = 1 \times 10^{-12}$$ at $$25^\circ C)$$ is titrated with $$\frac{2}{15}$$ M HCl in water at $$25^\circ C$$. The concentration of $$H^{+}$$ at equivalence point is $$(K_w = 1 \times 10^{-14}$$ at $$25^\circ C)$$
A solution of colourless salt H on boiling with excess NaOH produces a non-flammable gas. The gas evolution ceases after sometime. Upon addition of Zn dust to the same solution, the gas evolution restarts. The colourless salt(s) H is (are)
STATEMENT-1: Bromobenzene upon reaction with Br,/Fe gives 1,4-dibromobenzene as the major product.
and
STATEMENT-2: In bromobenzene, the inductive effect of the bromo group is more dominant than the mesomeric effect in directing the incoming electrophile.
STATEMENT-1: $$Pb^{4+}$$ compounds are stronger oxidizing agents than $$Sn^{4+}$$ compounds.
and
STATEMENT-2: The higher oxidation states for the group 14 elements are more stable for the heavier members of the group due to ‘inert pair effect’.
STATEMENT-1: The plot of atomic number (y-axis) versus number of neutrons (x-axis) for stable nuclei shows a curvature towards x-axis from the line of $$45^\circ$$ slope as the atomic numberis increased.
and
STATEMENT-2: Proton-proton electrostatic repulsions begin to overcome attractive forces involving protons and neutrons in heavier nuclides.
STATEMENT-1: For every chemical reaction at equilibrium, standard Gibbs energy of reaction is zero.
and
STATEMENT-2: At constant temperature and pressure, chemical reactions are spontaneous in the direction of decreasing Gibbs energy.
