1.

The standard adopted for the determination of atomic weight of elements is based on :

• H¹

• C¹²

• O¹⁶

• S³²

Law of multiple proportions is illustrated by one of the following pairs :

• N₂O and NO

• H₂S and SO₂

• NH₃ and Na₂O

• BeO and BeCl₂

Paramagnetism of oxygen is explained on the basis of its electronic configuration of

• ($\mathrm{\pi }$*2p_x)¹($\mathrm{\pi }$2p_y)¹

• ($\mathrm{\pi }$*2p_y)¹($\mathrm{\pi }$*2p_z)¹

• (σ*2s)¹($\mathrm{\pi }$2p_y)¹

• (σ*2s)¹($\mathrm{\pi }$2p_y)¹

The van der Waals' equation for a real gas is given by the formula $\left[\mathrm{P} + \frac{{\mathrm{n}}^2\mathrm{a}}{{\mathrm{V}}^2}\right]$ (V - nb) = nRT where, P, V, T and n are the pressure, volume, temperature and the number of moles of the gas. Which one is the correct interpretation for the parameter a?

• The parameter a accounts for the finite size of the molecule, not included temperature in the ideal gas law

• The parameter a accounts for the shape of gas phase molecules

• The parameter a accounts for intermolecular interaction's present in the molecule

• The parameter a has no physical significance and van der Waals' introduced it as a numerical correction factor only

Avogadro's hypothesis states that :

• the ideal gas consists of a large number of small particles called molecules

• under the same conditions of temperature and pressure equal volumes of gases contain the same number of molecules

• volume of a definite quantity of gas at constant pressure is directly proportional to absolute temperature

• a given mass of gas at constant pressure is directly proportional to absolute temperature

The observation that the ground state of nitrogen atom has 3 unpaired electrons in its electronic configuration and not otherwise is associated with:

• Pauli's exclusion principle

• Hund's rule of maximum multiplicity

• Heisenberg's uncertainty relation

• Ritz combination principle

Which of the following overlaps leads to bonding?

In the periodic table metallic character of elements shows one of the following trend :

• decreases down the group and increases across the period

• increases down the group and decreases across the period 

• increases across the period and also down the group

• decreases across the period and also down the group

Which of the following statements is correct ?

• All carbon to carbon bonds contain a σ-bond and one or more $\mathrm{\pi }$-bonds

• All carbon to hydrogen bonds are $\mathrm{\pi }$-bonds

• All oxygen to hydrogen bonds are hydrogen bonds

• All carbon to hydrogen bonds are $\mathrm{\pi }$-bonds

An example of a polar covalent compound is :

• KCl

• NaCl

• CCl₄

• HCl