JEE Advance - Chemistry (2005)

1
At constant temperature and volume, X decomposes as 2X(g) $$\to$$ 3Y(g) + 2Z(g); Px is the partial pressure of X.
Observation No. Time (in minute) Px (in mm of Hg)
1 0 800
2 100 400
3 200 200

(i) What is the order of the reaction to X?
(ii) Find the rate constant
(iii) Find the time for 75% completion of the reaction.
(iv) Find the total pressure when pressure of X is 700 mm of Hg
Answer
(A)
First order, $$6.93 \times 10^{-3}$$ min$$-1$$, 200 min, 950 mm Hg
1
The elevation in boiling point of a solution of 13.44 g of CuCl2 in 1kg of water using the following information will be (Molecular weight of CuCl2 = 134.4 and Kb = 0.52 K molal-1)
Answer
(A)
0.16
2
(a). For the reaction
Ag+ (aq) + Cl- (aq) $$\leftrightharpoons$$ AgCl (s)
Given:
Species $$\Delta G_f^o$$ (kJ/mol)
Ag+ (aq) +77
Cl- (aq) -129
AgCl (s) -109

Write the cell representation of above reaction and calculate $$E_{cell}^o$$ at 298 K. Also find the solubility product if AgCl.
(b) If 6.539 $$\times$$ 10-2 g of metallic zinc is added to 100 ml saturated solution of AgCl. Find the value of $${\log _{10}}{{\left[ {Z{n^{2 + }}} \right]} \over {{{\left[ {A{g^ + }} \right]}^2}}}$$. How many moles of Ag will be precipitated in the above reaction. Given that
Ag+ + e- $$\to$$ Ag; Eo = 0.80 V;
Zn2+ + 2e- $$\to$$ Zn; Eo = -0.76 V;
(It was given that atomic mass of Zn = 65.39)
Answer
A
C
2
Which species has the maximum number of lone pair of electrons on the central atom?
Answer
(D)
[I3]-
3
Find the velocity (ms-1) of electron in first Bohr's orbit of radius a0. Also find the de Broglie's wavelength (in m). Find the orbital angular momentum of 2p orbital of hydrogen atom in units of $$h/2 \pi$$.
Answer
(A)
v = 2.18 x 106 ms-1, 位 = 3.34 x 10-10 m, L = $$\sqrt{2} \frac{h}{2\pi}$$
3
The number of radial nodes of 3s and 2p orbitals are respectively
Answer
(A)
2, 0