Under which of the following condition is the relation $\mathrm{\Delta }H=\mathrm{\Delta }\underset{‾}{U}+p\mathrm{\Delta }V\backslash Delta\; H\; =\; \backslash Delta\; \backslash underline\{U\}\; +\; p\backslash Delta\; V$ valid for a closed system?

Given that the enthalpy of formation of $H_{2}OH\_2O$ is -68 kcal $mo{l}^{-1}mol^\{-1\}$, the enthalpy of formation of $O{H}^{-}OH^-$ ions 2 will be

The bond energies of C - C, C = C, H H and C - H linkages are 350, 600, 400, and 410 kJ per mole respectively. The heat of hydrogenation of ethylene is

Enthalpy of $C{H}_4+\frac{1}{2}{O}_2⟶C{H}_{3}OHCH\_4+\backslash frac12O\_2\backslash longrightarrow\; CH\_3OH$ is negative If enthalpy of combustion of methane and $C{H}_{3}OHCH\_3OH$ are x and y respectively, then which relation is correct?

If an endothermic reaction occurs spontaneously at constant T and P, then which of the following is true?

Standard entropy of $X_2,Y_{2}X\_2,Y\_2$ and $X{Y}_{3}XY\_3$ are 60, 40 and 50 $J{K}^{-1}mo{l}^{-1}J\; K^\{-1\}\backslash ,mol^\{-1\}$, respectively. For the reaction $\frac{1}{2}{X}_2+\frac{3}{2}{Y}_2⟶X{Y}_3\backslash frac12\; X\_2+\backslash frac32Y\_2\backslash longrightarrow\; XY\_3$ $\mathrm{\Delta }H=-30kJ,\backslash Delta\; H=-30\backslash ,kJ,$ to be at equilibrium, the temperature will be

For a particular reversible reaction at temperature T, $\mathrm{\Delta }H\backslash Delta\; H$ and $\mathrm{\Delta }S\backslash Delta\; S$ were found to be both +ve. If $T_{e}T\_e$ is the temperature at equilibrium, the reaction would be spontaneous when

The incorrect expression among the following is :

A gas present in a cylinder fitted with a frictionless piston expands against a constant pressure of 1 bar from a volume of 2 L to 12 L. In doing so, it absorbs 820 J heat from the surrounding. The change in internal energy during the process is :

An insulated container is divided into two compartments. One compartment contains an ideal gas at a pressure P and temperature T while in the other compartment there is perfect vacuum. If a hole is made in the partition wall, which of the following will be true?