Δ H and ΔS for a reaction are +30.558 kJ mol^-1 and 0.066 kJ K^-1mol^-1 at 1 atm pressure. The temperature at which free energy change is equal to zero and the nature of the reaction below this temperature are :

• 483 K, spontaneous

• 443 K, non-spontaneous

• 443 K, spontaneous

• 463 K, non-spontaneous

The enthalpy of vaporization of substance is 840 J mol^-1 and its boiling point is -173°C. Its entropy of vaporization is :

• 42 J mol^-1 K^-1

• 21 J mol^-1 K^-1

• 84 J mol^-1 K^-1

• 8.4 J mol^-1 K^-1

Given the following thermochemical equations:

Zn + $\frac{1}{2}$O₂ → ZnO + 84,000 cal

Hg + $\frac{1}{2}$O₂ → HgO + 21,700 cal

Accordingly the heat of reaction for the following reaction, Zn + HgO → Hg + heat is:

• 105,700 cal

• 61,000 cal

• 62,300 cal

• 60,000 cal

The law of thermodynamics formulated by Dr.N. Nernst is :

• first law of thermodynamics

• second law of thermodynamics

• third law of thermodynamics

• both (a) and (b)

115.

Heat of neutralization will be minimum for which of the following combination?

• NaOH + H₂SO₄

• NH₄OH + CH₃COOH

• NaOH + HCl

• NaOH + CH₃COOH

2 moles of helium gas expanded isothermally and irreversible at 27°C from volume 1 dm³ to 1 m³ at constant pressure of 100 kPa. Calculate the work done.

• 99900 kJ

• 99900 J

• 34464.65 kJ

• 34464.65 J

Heat of formation of SO₂ is -298 kJ. What is the heat of combustion of 4 g of S ?

• + 37 kJ

• -37.15 kJ

• + 298 kJ

• 18.6 kJ

For the reaction

PCl₅(g) → PCl₃(g) + Cl₂(g)

• ΔH = ΔE

• ΔH > ΔE

• ΔH < ΔE

• None of these

Which of the following is not a state function?

• Internal energy

• Enthalpy

• Work

• Entropy

Enthalpy (H) is equal to

• internal energy (E)

• product of pressure (p) and volume (V) of gas

• internal energy (E)+ pV

• work (W) done by a system