Enthalpy of formation of HF and HCl are -161 kJ and -92 kJ respectively. Which of the following statements is incorrect?

• HCl is more stable than HF

• HF and HCl are exothermic compounds

• The affinity of fluorine to hydrogen is greaterthan the affinity of chlorine to hydrogen

• HF is more stable than HCl

The enthalpy of reaction,

${\mathrm{H}}_2\left(\mathrm{g}\right) +\frac{1}{2}{\mathrm{O}}_2\left(\mathrm{g}\right) \to {\mathrm{H}}_2\mathrm{O}\left(\mathrm{g}\right) \mathrm{is}\hspace{0.17em}∆{\mathrm{H}}_1 \mathrm{and} \mathrm{that} \mathrm{of} H_2\left(\mathrm{g}\right) +\frac{1}{2}{\mathrm{O}}_2\left(\mathrm{g}\right) \to {\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right) \mathrm{is}\hspace{0.17em}∆{\mathrm{H}}_2.\mathrm{Then}$

• ΔH₁ < ΔH₂

• ΔH₁ + ΔH₂ = 0

• ΔH₁ > ΔH₂

• ΔH₁ = ΔH₂

The enthalpies of formation of Al₂O₃ and Cr₂O₃ are -1596 kJ and -1134 kJ respectively. $∆$H for the reaction,

2Al + Cr₂O₃  → 2Cr+ Al₂O₃ is

• -2730 kJ

• -462 kJ

• -1365 kJ

• +2730 kJ

A process is taking place at constant temperature and pressure. Then

• ΔH = ΔE=0

• ΔH= TΔS

• ΔH= 0

• ΔS= 0

The enthalpy of combustion of methane at 25°C is 890 kJ. The heat liberated when 3.2 g of methane burnt in air is

• 445 kJ

• 278 kJ

• -890 kJ

• 178 kJ

A mixture of two moles of carbon monoxide and one mole of oxygen, in a closed vessel is ignited to convert the carbon monoxide to carbon dioxide. If $∆$H is the enthalpy change and $∆$E is the change in internal energy, then

• $∆\mathrm{H} > ∆\mathrm{E}$

• $∆\mathrm{H} < ∆\mathrm{E}$

• $∆\mathrm{H} = ∆\mathrm{E}$

• the relationship depends on the capacity of the vessel

For a system in equilibrium, $∆$G= 0, under conditions of constant ...............

• temperature and pressure

• temperature and volume

• pressure and volume

• energy and volume

Molar heat of vaporisation of a liquid is 6 kJ mol^-1. If the entropy change is 16 J mol^-1 K^-1, the boiling point of the liquid is:

• 375°C

• 375 K

• 273 K

• 102°C

489.

0.06 mole of KNO₃ solid is added to 100 cm³ of water at 298K. The enthalpy of KNO₃ aqueous solution is 35.8 kJ mol^-1. After the solute is dissolved the temperature of the solution will be:

• 293 K

• 298 K

• 301 K

• 304 K

ΔG° vs T plot in the Ellingham's diagram slopes upwards for the reactions:

• Mg+ 1/2O₂ → MgO

• 2Ag + 1/2O₂ → Ag₂O

• C + 1/2O₂ → CO

• CO + 1/2O₂ → CO₂