The heat of combustion of carbon to CO₂ is -395.5 kJ/mol. The heat released upon the formation of 35.2 g CO₂ from carbon and oxygen gas is 

• -315 kJ

• +315 kJ

• -630 kJ

• -630 kJ

The formation of the oxide ion O^2- (g), from oxygen atom requires first an exothermic and then an endothermic step as shown below,


Thus, the process of formation of O^2- in the gas phase is unfavourable even though O^2- is isoelectronic with neon. It is due to the fact that

• electron repulsion outweighs the stability gained by achieving a noble gas configuration

• O^- ion has comparatively smaller size that oxygen atom

• oxygen is more electronegative

• oxygen is more electronegative

Consider the following processes Δ H (kJ/mol)

1/2 A →                               +150
3B   → 2 C + D                     -125
E + A  → 2D                        +350

For  B + D   → E + 2C, ΔH will be 

• 525 kJ/mol

• -175 kJ/mol

• -325 kJ /mol

• -325 kJ /mol

274.

Standard entropies X₂, Y₂ and XY₂ are 60, 40 and 50 J K^-1 mol^-1 respectively for the reaction


equilibrium, the temperature should be

• 750 K

• 1000 K 

• 1250 K

• 1250 K

Three moles of an ideal gas expanded spontaneously into the vacuum. The work done will be

• infinte

• 3 J

• 9 J

• 9 J

Match List I (equation) with List II (types of the process) and select the correct option.

• A	B	C	D
  1	2	3	4

• A	B	C	D
  3	4	2	1

• A	B	C	D
  4	1	2	3

• A	B	C	D
  4	1	2	3

The values of ΔH and ΔS for the reaction, C_(graphite) + CO₂(g) → 2 CO (g) are 170 kJ and 170 JK^-1 respectively. This reaction will be spontaneous at

• 710 K 

• 910 K

• 1110 K

• 1110 K

Which of the following are not state functions?
I) q + W
II) q
III) W
IV) H-TS

• (I) and (IV)

• (II) (III) and (IV)

• (I), (II) and (III)

• (I), (II) and (III)

For the gas phase, reaction,

PCl₅ (g) ⇌ PCl₃ (g) Cl₂ (g)
Which of the following conditions are correct?

• Δ H = 0 and ΔS > 0

• ΔH >0 and ΔS > 0

• Δ H < 0 and ΔS < 0

• Δ H < 0 and ΔS < 0

Consider the following reactions:


Enthalpy of formation of H₂O (l) is:

• - x₂ kJ mol^-1

• + x₃ kJ mol^-1

• - x₄ kJ mol^-1

• - x₄ kJ mol^-1