The one electron species having ionization energy of 54.4 eV is :

• H

• He⁺

• B⁴⁺

• Li²⁺

The correct set of quantum numbers (n, l and m respectively) for the unpaired electron of chlorine atom is :

• 2, 1, 0

• 2, 1, 1

• 3, 1, 1

• 3, 2, 1

3.

Which of the following contains maximum number of molecules ?

• 200 cc of NH₃ at STP

• 100 cc of CO₂ at STP

• 150 cc of N₂ at STP

• 500 cc of SO₂ at STP

The numerical value of $\frac{\mathrm{N}}{\mathrm{n}}$ (where, N is the number of molecules in a given sample of gas and n is the number of moles of the gas) is :

• 8.314

• 6.02 × 10²³

• 0.0821

• 1.66 × 10^-19

The mass of 11.2 L of ammonia gas at STP is:

• 8.5 g

• 85 g

• 17 g

• 1.7 g

Consider the ions : K⁺, S^2-, Cl^- and Ca²⁺. The radii of these ionic species follow the order

• Ca²⁺ > K⁺ > Cl^- > S^2-

• Cl^- > S^2- > K⁺ > Ca²⁺

• S^2- > Cl^- > K⁺ > Ca²⁺

• Ca²⁺ > S^2- > Cl^- > Ca²⁺

Identify the correct statement from below, concerning the structure of CH₂ = C = CH₂

• The molecule is planar

• One of the three carbon atoms is in an sp³ hybridized state

• The molecule is non-planar with the two -CH₂ groups being in planes perpendicular to each other

• All the carbon atoms are sp-hybridized

Molecular shapes of SF₄, CF₄, XeF₄ are :

• the same with 2, 0 and 1 lone pair of electron respectively

• the same with 1, 1 and 1 lone pair of electrons respectively

• different with 0, 1 and 2 lone pair of electrons respectively

• different with 1, 0 and 2 lone pair of electrons respectively

The enthalpy of a monoatomic gas at T Kelvin is :

• $\frac{7}{2}$RT

• $\frac{5}{2}$RT

• $\frac{1}{2}$RT

• $\frac{1}{2}$

The enthalpy change for the transition of liquid water to steam is 40.8 kJ mol^-1 at 373 K. What is the entropy of vaporisation of water ?

• 209.4

• 109.4

• -109.4

• -209.4