Given that $∆{\mathrm{H}}_{\mathrm{f}}$(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 10⁴ J/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 $\stackrel{°}{\mathrm{A}}$ and HI= 1.6 $\stackrel{°}{\mathrm{{\rm A}}}$.  The ratio of fraction of electric charge, $\mathrm{\delta }$, 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

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

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

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

• 0.1

• 10

• 1

• 0.4