Heat of neutralisation of oxalic acid is -25.4 K cal mol^-1 using strong base, NaOH. Hence enthalpy change of the process is $H_2{C}_2{O}_4\rightleftharpoons 2H^{+}+C_2{H_4}^{2-}$is-

5 moles of nitrogen gas are enclosed in an adiabatic cylindrical vessel. The piston itself is a rigid light cylindrical container containing 3 moles of Helium gas. There is a heater which gives out a power 100 cal to the nitrogen gas. A power of 30 cal is transferred to Helium through the bottom surface of the piston.

The rate of increment of temperature of the nitrogen gas assuming that the piston moves slowly :

The correct option for free expansion of an ideal gas under adiabatic condition is:

During the isothermal mixing of ideal gases at pressure, p, the entropy change per mole for the mixing process is-R $\sum x_i \ln x_i$ where x₁, x₂,....,x_i are the mole fractions of the components, 1, 2,....,i of the mixture. Assuming ideal gas behavior, calculate $∆S$ for the mixing of 0.8 mole of N₂ and 0.2 mole of O₂.(at ${25}^{\circ }C$ and 0.9 atm) [1 eu = cal/deg]

An ideal gas can be expanded from an initial state to a certain volume through two different processes, (A) $P{V}^2=K$ (B) $P=K{V}^2$, where K is a positive constant. Then, choose the correct option from the following.

Heat of hydrogenation of ethene is x₁ and that of benzene is x₂. Hence resonance energy is-

$$\begin{gathered} {\mathrm{C}}_2{\mathrm{H}}_6\left(\mathrm{g}\right)+3.5{\mathrm{O}}_2\left(\mathrm{g}\right)\to 2{\mathrm{CO}}_2\left(\mathrm{g}\right)+3{\mathrm{H}}_2\mathrm{O}\left(\mathrm{g}\right) \\ ∆{\mathrm{S}}_{\mathrm{vap}}\left({\mathrm{H}}_2\mathrm{O}, \mathrm{l}\right)={\mathrm{x}}_1 \mathrm{cal} {\mathrm{K}}^{-1}\left(\mathrm{b}.\mathrm{p}. +{\mathrm{T}}_1\right) \\ ∆{\mathrm{H}}_{\mathrm{f}}\left({\mathrm{H}}_2\mathrm{O}, \mathrm{l}\right)={\mathrm{x}}_2; ∆{\mathrm{H}}_{\mathrm{f}}\left({\mathrm{CO}}_2\right)={\mathrm{x}}_3, ∆{\mathrm{H}}_{\mathrm{f}}\left({\mathrm{C}}_2{\mathrm{H}}_6\right)={\mathrm{x}}_4 \\ \mathrm{Hence} ∆\mathrm{H} \mathrm{for} \mathrm{the} \mathrm{reaction} \mathrm{is}- \end{gathered}$$

The bond energies of $\mathrm{C}\equiv \mathrm{C}$, C-H, H-H, and C=C are 198, 98, 103 and145 kcal respectively.

The enthalpy change of the reaction $\mathrm{HC}\equiv \mathrm{CH}+{\mathrm{H}}_2\to {\mathrm{C}}_2{\mathrm{H}}_4$ would be-

$H_2\left(g\right)+\frac{1}{2}{O}_2\left(g\right)\to H_{2}O\left(l\right)$

B.E. (H-H) = x₁; B.E. (O=O) = x₂ B.E. (O-H) = x₃

Latent heat of vaporization of water liquid into water vapour = x₄, then $∆H_f$(heat of formation of liquid water) is-

In a process the pressure of a gas is inversely proportional to the square of the volume. If temperature of the gas is increased, then work done on the gas-

The enthalpies of formation of CO₂(g) and CO(g) at 298 K are in the ratio 2.57 : 1. For the reaction,

$$\begin{gathered} C{O}_2\left(g\right)+C\left(s\right)\to 2 CO\left(g\right), ∆H=172.5 kJ, \\ ∆H_f of CO\left(g\right) is \end{gathered}$$

In an adiabatic expansion the product of pressure and volume-

The molar entropy of the vapourization of acetic acid is 14.4 cal K^-1 mol^-1 at its boiling point ${118}^{\circ }C$. The latent heat of vapourization of acetic acid is-

100 ml of 0.3 M HCl solution is mixed with 100 ml of 0.35 M NaOH solution. The amount of heat liberated is

The quantity ${\delta }_q$ i.e. heat absorbed an infinitesimal process is

An ideal gas absorbs 2000 cal of heat from a heat reservoir and does mechanical work equivalent to 4200 J. The change in internal energy of the gas is-

For an ideal gas four processes are marked as 1, 2, 3 and 4 on P-V diagram as shown in figure. The amount of heat supplied to the gas in the process 1, 2, 3 and 4 are Q₁, Q₂, Q₃ and Q₄ repectively, then correct order of heat supplied to the gas is

[AB is process-1, AC is process-2, AD is adiabatic process-3 and AE is process-4]

The latent heat of vapourisation of water at ${25}^{\circ }C$ is 10.5 kcal mol^-1 and the standard heat of formation of liquid water is -68.3 kcal. The enthalpy change of the reaction

$H_2\left(g\right)+\left(1/2\right)O_2\left(g\right)\to H_{2}O\left(g\right)$ is therefore,

3. 78.8 kcal

Which of the following thermodynamic quantities is an outcome of the second law of thermodynamics?

Given the Gibbs free energy change, ΔG º = + 63.3 kJ, for the following reaction,

${\mathrm{Ag}}_2{\mathrm{CO}}_3\left(\mathrm{g}\right)\to 2{\mathrm{Ag}}^{+} \left(\mathrm{aq}\right) +{\mathrm{CO}}_3^{2-} \left(\mathrm{aq}\right)$

K_sp of ${\mathrm{Ag}}_2{\mathrm{CO}}_3$(s) in water at 25 ºC is (R = 8.314 JK^–1 mol^–1)

From the following data of $∆H$, of the following reactions,

$$\begin{gathered} C\left(s\right)+\frac{1}{2}{O}_2\to CO\left(g\right) ;∆H=-110 kJ \\ C\left(s\right)+H_{2}O\to CO\left(g\right)+H_2\left(g\right) ;∆H=132 kJ \end{gathered}$$

What is the mole composition of the mixture of steam and oxygen on being passed over coke at 1273 K, keeping temperature constant.

The intermediate SiH₂ is formed in the thermal decomposition of silicon hydrides. Calculate $∆H_f^{\circ }$ of SiH₂ given the following reactions

$$\begin{gathered} S{i}_2{H}_6\left(g\right)+H_2\left(g\right)\to 2Si{H}_4\left(g\right); ∆H^{\circ }=-11.7 kJ/mol \\ Si{H}_4\left(g\right)\to Si{H}_2\left(g\right)+H_2\left(g\right); ∆H^{\circ }=+239.7 kJ/mol \\ ∆H_f, S{i}_2{H}_6\left(g\right)=+80.3 kJ mo{l}^{-1} \end{gathered}$$

A certain vessel X has water and nitrogen gas at a total pressure of 2 atm. and 300 K. All the contents of the vessel are transferred to another vessel Y having half the capacity of the vessel X. The pressiure of N₂ in this vessel was 3.8 atm. at 300 K. The vessel Y is heated to 320 K and the total pressure observed was 4.32 atm. Calculate the enthalpy of vapourisation of water assuming it to be independent of temperature. Also assume the volume occupied by the gases in a vessel is equal to the volume of the vessel.

For a reaction, $A+B\to AB, ∆c_P$ is given by the equation $40+5\times {10}^{-3} T J{K}^4$ in the temperature range 300-600 K. The enthalpy of the reaction at 300 K is -25.0 KJ. Calculate the enthalpy of the reaction at 450 K.

The heat of combustion of ethylene at ${17}^{\circ }C$ and at constant volume is -332.19 kcals. What is the value at constant pressure, given that water is in liquid state ?

The enthalpies of the following reactions are shown alongwith.

$$\begin{gathered} \frac{1}{2}{H}_2\left(g\right)+\frac{1}{2}{O}_2\left(g\right)\to OH\left(g\right) ; ∆H=42.09 kJ mo{l}^{-1} \\ {H}_2\left(g\right)\to 2H\left(g\right); ∆H=435.89 kJ mo{l}^{-1} \\ {O}_2\left(g\right)\to 2O\left(g\right); ∆H=495.05 kJ mo{l}^{-1} \end{gathered}$$

Calculate the O-H bond energies for the hydroxyl radical.

The bond dissociation enthalpy of gaseous H₂, Cl₂ and HCl are 435, 243 and 431 kJ mol^-1, respectively. Calculate the enthalpy of formation of HCl gas.

A gas mixture consisting of 3.67 litres of ethylene and methane on complete combustion at ${25}^{\circ }C$ produces 6.11 litres of CO₂. Find out the amount of heat evolved on burning one litre of the gas mixture. The heats of combustion of ethylene and methane are -1423 and -891 kJ mol^-1, respectively, at ${25}^{\circ }C$.

The enthalpy of formation of CO₂(g), H₂O(l) and propene (g) are -393.5, -285.8 and 20.42 kJ mol^-1 respectively. The enthalpy change for the combustion of cyclopropane at 298 K will be -

(The enthalpy of isomerisation of cyclopropane to propene is -33.0 kJ mol^-1. )

The bond dissociation energies of $X_2 , Y_2$ and XY are in the ratio of 1 : 0.5 : 1. ∆H for the formation of XY is –200 kJ mol^–1. The bond dissociation energy of X₂ will be