The radius of which of the following orbit is same as that of the first Bohr's orbit of hydrogen atom?

• Li²⁺ (n = 2)

• Li²⁺ (n = 3)

• Be³⁺ (n = 2)

• He⁺ ( n = 2)

Van der waals' real gas, acts as an ideal gas at which condition?

• High temperature, low pressure

• Low temperature, high pressure

• High temperature, high pressure

• Low temperature, low pressure

Ionisation energy in group 1A varies in the decreasing order as

• Li > Na > K > Cs

• Na > Li > K > Cs

• Li > Cs > K  Na

• K > Cs > Na > Li

Intramolecular hydrogen bond is present in

• water

• o-nitrophenol

• p-nitrophenol

• methylamine

Which one of the following species acts as both Bronsted acid and base?

• H₂PO${}_2^{-}$

• HPO${}_3^{2-}$

• HPO${}_4^{2-}$

• All of these

The reaction, SO₂ + O₂ → 2SO₂ + Heat.

The equilibrium reaction proceeds in forward direction by

• addition of O₂

• removal of O₂

• addition of inert gas

• cannot proceed

Which is soluble in NaNO₃ and dil. HCl mixture and forming salt?

• (CH₃)₃CNH₂

• (CH₃)₂CHNH₂

• (CH₃)₂NH

• (CH₃)₃N

18.

An example of a non-stoichiometric compound is

• PbO

• NiO₂

• Al₂O₃

• Fe₃O₄

Which of the following type of forces are present in vulcanised rubber?

• Weakest intermolecular forces

• Hydrogen bonding

• Three dimensional network of bonds

• Metallic bonding

If  H_f (H₂O) is -286.20 kJ mol^-1, then  H${}_{\mathrm{f}}^{°}$  (OH^-) is

• -228.88 kJ mol^-1

• +228.88 kJ mol^-1

• -343.52 kJ mol^-1

• +343.52 kJ mol^-1