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JEE Chemistry Solved Question Paper 2009

Multiple Choice Questions

Given that $∆ H_{f}$ (H) = 218 kJ / mol, express the H-H bond energy in kcal/mol.

52.15
911
104
52153

The wavelengths of electron waves in two orbits is 3: 5. The ratio of kinetic energy of electrons will be

25: 9
5: 3
9: 25
3: 5

Electrons with a kinetic energy of 6.023 x 10⁴J/mol are evolved from the surface of a metal, when it is exposed to radiation of wavelength of 600 nm. The minimum amount of energy required to remove an electron from the metal atom is

2.3125 x 10^-19 J
3 x 10^-19 J
6.02 x 10^-19 J
6.62 x 10^-19 J

Dipole moment of HCl = 1.03 D, HI = 0.38 D. Bond length of HCl = 1.3 $\overset{°}{A}$ and HI= 1.6 $\overset{°}{Α}$ . The ratio of fraction of electric charge, $δ$ , existing on each atom in HCl and HI is

12: 1
2.7: 1
3.3: 1
1: 3.3

SiCl₄ on hydrolysis forms 'X' and HCl Compound 'X' loses water at l000°C and gives 'Y'. Compounds 'X' and 'Y' respectively are

H₂SiCl₆, SiO₂
H₄SiO₄, Si
SiO₂, Si
H₄SiO₄, SiO₂

1.5 g of CdCl₂ was found to contain 0.9 g of Cd. Calculate the atomic weight of Cd.

118
112
106.5
53.25

The average kinetic energy of one molecule of an ideal gas at 27°C and 1 atm pressure is

900 cal K^-1mol^-1
6.21 X 10^-21 JK^-1 molecule^-1
336.7 JK^-1 molecule^-1
3741.3 JK^-1 mol^-1

8.
Assertion (A): K, Rb and Cs form superoxides.
Reason (R): The stability of the superoxides increases from 'K' to 'Cs' due to decrease in lattice energy.
The correct answer is

Both (A) and (R) are true and (R) is the correct explanation of (A).

Both (A) and (R) are true but (R) is not the correct explanation of (A)

(A) is true but (R) is not true

(A) is not true but (R) is true

(A) is true but (R) is not true

Superoxides are the species having an $O - O$ bond and O in an oxidation state of $- \frac{1}{2}$ (superoxide ion is $O_{2}^{-}$ ). Usually these are formed by active metals such as KO₂, RbO₂ and CsO₂. For the salts of larger anions (like $O_{2}^{-}$ ), lattice energy increases in a group. Since, lattice energy is the driving force for the formation of an ionic compound and its stability, the stability of the superoxides from 'K' to 'Cs' also increases.

How many 'mL' of perhydrol is required to produce sufficient oxygen which can be used to completely convert 2 L of SO₂ gas to SO₃ gas?

10 mL
5 mL
20 mL
30 mL

10.

pH of a buffer solution decreases by 0.02 units when 0.12 g of acetic acid is added to 250 mL of a buffer solution of acetic acid and potassium acetate at 27C. The buffer capacity of the solution is