At standard conditions, the change in enthalpy for the following reaction is –109 kJ ${\mathrm{mol}}^{-1}$ 

${\mathrm{H}}_{2\left(\mathrm{g}\right)}+{\mathrm{Br}}_{2\left(\mathrm{g}\right)}\to 2{\mathrm{HBr}}_{\left(\mathrm{g}\right)}$

Given that the bond energy of H ₂ and Br ₂ is 435 kJ ${\mathrm{mol}}^{-1}$ and 192 kJ ${\mathrm{mol}}^{-1}$, respectively, what is the bond energy (in kJ ${\mathrm{mol}}^{-1}$) of HBr?

1. 368

2. 736

3. 518

4. 259

${∆}_{\mathrm{lattice}}{\mathrm{H}}^{⊝}$ or U for NaBr is : 

${Given\; : \; ∆}_{\mathrm{sub}}{\mathrm{H}}^{⊝}$ for sodium metal$=108.4 \mathrm{kJ} {\mathrm{mol}}^{-1}$, ionisation enthalpy of sodium$=496 \mathrm{kJ} {\mathrm{mol}}^{-1}$, electron gain enthalpy of bromine$=-325 \mathrm{kJ} {\mathrm{mol}}^{-1}$, bond dissociation enthalpy of bromine$=192 \mathrm{kJ} {\mathrm{mol}}^{-1}$, ${∆}_{\mathrm{f}}{\mathrm{H}}^{⊝}$ for NaBr(s)$=-360.1 \mathrm{kJ} {\mathrm{mol}}^{-1}$

1. $+735.5 \mathrm{kJ} {\mathrm{mol}}^{-1}$

2. $+435.5 \mathrm{kJ} {\mathrm{mol}}^{-1}$

3. $+489.5 \mathrm{kJ} {\mathrm{mol}}^{-1}$

4. $+230.5 \mathrm{kJ} {\mathrm{mol}}^{-1}$

The amount of heat required to raise the temperature of one mole of the substance by 1 K is called its:

1. Molar heat capacity

2. Entropy

3. Thermal capacity

4. Specific heat

In a constant volume calorimeter 3.5g of a gas

(mol.wt.28) was burnt in excess O${}_2$ at 298 K. The

increase in temperature is 0.45 K due to combus-

tion, If Heat capacity of calorimeter is 2.5 kJ/K

the value of $∆$E is

1. 90 KJ/m

2. 9 kJ/m

3. 45 kJ/m

4. 18 kJ/m

The free energy change $(∆G°)$ is negative when -

1. The surroundings do no electrical work on the system.

2. The surroundings do electrical work on the system.

3. The system does electrical work on the surroundings.

4. The system does no electrical work on the surroundings.

Which of the following statement is true for $∆$G?

1. It is always proportional to $∆$H

2. It may be less than or greater than or equal to $∆$H

3. It is always greater than $∆$H

4. It is always less than $∆$H

The Gibbs free energy is defined as

1. G=H$-$T.S

2. G=H+T.S

3. G=E$-$ T.S

4. G=E+ T.s

Which one of the following reactions obeys  ∆ H ≠ ∆ E.?

Standard molar enthalpy of formation of ${\mathrm{CO}}_2$ is equal to

1. Zero

2. The standard molar enthalpy of combustion of gaseous carbon.

3. The sum of standard molar enthalpies of formation Of CO and ${\mathrm{CO}}_2$

4. The standard molar enthalpy of combustion of carbon (graphite)

Which of the following statements is false?

1. Work is a state function.

2. Temperature is a state function.

3. Density is a state function.

4. Entropy is state function.