The temperature of the system decreases in an :

• adiabatic compression

• isothermal compression

• isothermal expansion

• adiabatic expansion

The species among the following, which can act as an acid and a base is :

• HS${\mathrm{O}}_4^{2-}$

• S${\mathrm{O}}_4^{2-}$

• H₃O⁺

• Cl^-

A certain reaction is at equilibrium at 82°C and the enthalpy change for this reaction is 21.3 kJ. The value of $∆$S(JK^-1mol^-1) for the reaction is :

• 55.0

• 60.0

• 68.5

• 120.0

If in the reaction N₂O₄ $\rightleftharpoons$ 2NO₂ , x is that part of N₂O₄ which dissociates, then the number of molecules at equilibrium will be :

• 1

• 3

• (1 + X)

• (1 + X)²

The hybridisation of the central atom in BrF₅ molecule is :

• sp³

• dsp²

• sp³d²

• d³sp³

The ccrrect statement with regard to ${\mathrm{H}}_2^{+}$ and ${\mathrm{H}}_2^{-}$ is :

• both ${\mathrm{H}}_2^{+}$ and ${\mathrm{H}}_2^{-}$ are equally stable

• both ${\mathrm{H}}_2^{+}$ and ${\mathrm{H}}_2^{-}$ do not exist

• ${\mathrm{H}}_2^{-}$ is more stable than ${\mathrm{H}}_2^{+}$

• ${\mathrm{H}}_2^{+}$ is more stable than ${\mathrm{H}}_2^{-}$

17.

A covalent molecule AB₃ has pyramidal structure. The number of lone pair and bond pair of electrons in the molecule a respectively :

• 2 and 2

• 0 and 2

• 3 and 1

• 1 and 3

The correct order of ionisation energy of C, N, O, F is :

• F < 0 < N < C

• F < N < C < 0

• C < N < 0 < F

• C < 0 < N < F

For a reaction, A + 2B $\to$ C, the amount of C formed by starting the reaction with 5 moles of A and 8 moles of B is :

• 5 mol

• 8 mol

• 16 mol

• 4 mol

In the eclipsed conformation of ethane, the dihedral angle between the hydrogen atoms of adjacent methyl groups is :

• 60°

• 120°

• 0°

• 180°