Identify the correct statements about the following stoichiometric equation.

$$ a \mathrm{P}_4+b^{-} \mathrm{OH}+c \mathrm{H}_2 \mathrm{O} \longrightarrow d \mathrm{PH}_3+e \mathrm{H}_2 \mathrm{PO}_2^{-} $$

I. $a+b+c=5$

II. $b+c-e=3$

III. The oxidation state of P in $\mathrm{H}_2 \mathrm{PO}_2^{-}$is +l .

5 moles of a gas is allowed to pass through a series of changes as shown in the graph, in a cyclic process. The processes $C \rightarrow A, B \rightarrow C$ and $A \rightarrow B$ respectively are

1 mole of an ideal gas is allowed to expand isothermally and reversibly from $\mathrm{1L}$ to 5 L at 300 K . The change in enthalpy (in kJ ) is $\left(R=8.3 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}\right)$

Consider the following equilibrium reaction in gaseous state at $T(\mathrm{~K})$.

$$ A+2 B \rightleftharpoons 2 C+D $$

The initial concentration of $B$ is 1.5 times that of $A$. At equilibrium, the concentrations of $A$ and $B$ are equal. The equilibrium constant for the reaction is