${∆}_{\mathrm{lattice}}{\mathrm{H}}^{⊝}$ 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 enthalpy of combustion of methane, graphite, and dihydrogen at 298 K are,

–890.3 kJ mol^-1 , –393.5 kJ mol^-1, and –285.8 kJ mol^-1 respectively.

The enthalpy of formation of CH₄(g) is-

1.  –74.8 kJ mol^-1

2.  –52.27 kJ mol^-1

3.  +74.8 kJ mol^-1

4.  +52.26 kJ mol^-1

 For the reaction A + B → C + D + q (kJ/mol), entropy change is positive. The reaction will be

1. Possible only at high temperature

2. Possible only at low temperature

3. Not possible at any temperature

4. Possible at any temperature

For the reaction, $2C{}^{}\to C{}^{}$, the value of ∆H and ∆S  are respectively -

1. $∆\mathrm{H}=0$ $,$ $∆\mathrm{S}=-\mathrm{ve}$

2. $∆\mathrm{H}=0$ $,$ $∆\mathrm{S}=0$

3. $∆\mathrm{H}=$ $-\mathrm{ve}$ $,$ $∆\mathrm{S}$ $=$ $-\mathrm{ve}$

4. $∆\mathrm{H}=$ $+\mathrm{ve}$ $,$ $∆\mathrm{S}=$ $+\mathrm{ve}$

At standard conditions, if the change in the 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

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

1. Molar heat

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