${\mathrm{\Delta H}}_{\mathrm{f}}^{°}$ (C₂H₄) , ${\mathrm{\Delta H}}_{\mathrm{f}}^{°}$ (C₂H₆) are x₁ and x₂ kcalmol^-1 respectively. Then heat of hydrogenation of C₂H₄ is :

• x₁ + x₂

• x₁ - x₂

• -(x₁ - x₂)

• x₁ + 2x₂

The heat of formation of C₁₂H₂₂O₁₁ (s) , CO₂ (g) and (H₂O) are - 530 , -94.3 and- 68.3 kcalmol^-1 respectively. The amount of C₁₂H₂₂O₁₁ to supply 2700 kcal of energy is :

• 382.70 g

• 832.74 g

• 463.9 g

• 684.0 g

Spontaneous adsorption of gas on solid surface is an exothermic process because :

• $\mathrm{\Delta }$H increases for system

• $\mathrm{\Delta }$S increases for gas

• $\mathrm{\Delta }$S decreases for gas

• $\mathrm{\Delta }$G increases for gas

Fermentation is :

• reversible

• exothermic

• endothermic

• None of these

Assertion : A reaction which is spontaneous and accompanied by decrease of randomness must be exothermic.

Reason : All exothermic reactions are accompanied by decrease of randomness.

• If both assertion and reason are true and reason is the correct explanation of assertion

• If both assertion and reason are true but reason is not the correct explanation of assertion

• If assertion is true but reason is false

• If both assertion and reason are false.

For the complete combustion of 4 L ethane , how much oxygen is required ?

• 14 L

• 4 L

• 8 L

• 12 L

For the reaction of one mole of zinc dust with one mole of sulphuric acid in a bomb calorimeter, $∆$U and w correspond to

• $∆$U < 0, w = 0

• $∆$U < 0, w < 0

• $∆$U > 0, w = 0

• $∆$U > 0, w > 0

68.

One mole of which of the following has the highest entropy ?

• Liquid nitrogen

• Hydrogen gas

• Mercury

• Diamond

1 mole of H₂SO₄ is mixed with 2 moles of NaOH .The heat evolved will be :

• 57.3 kJ

• 2 x 57.3 kJ

• 57.3/2 kJ

• Cannot be predicted

One mole. of a perfect gas expands isothermally to ten times of its original volume. The change in entropy is :

• 0.1 R

• 2.303 R

• 10.0 R

• 100.0 R