Consider the following unit volumes of energy, A : 1 L atm, B : 1 erg, C : 1 J, D : 1 k cal, increasing order of these values is

R = 0.0821 L atm ${\mathrm{mol}}^{-1}{\mathrm{K}}^{-1}$

  = 8.314 $\times {10}^7 \mathrm{ergs} {\mathrm{mol}}^{-1} {\mathrm{K}}^{-1},$

  = 8.314 J ${\mathrm{mol}}^{-1}{\mathrm{K}}^{-1}$

   = 0.002 kcal ${\mathrm{mol}}^{-1}{\mathrm{K}}^{-1}$

   = x

$\therefore 1 \mathrm{L} \mathrm{atm} = \frac{\mathrm{x}}{0.0821} = \mathrm{A}$

$1 \mathrm{erg} = \frac{\mathrm{x}}{8.314\times {10}^7} = \mathrm{B}$

$1 \mathrm{J} = \frac{\mathrm{x}}{8.314} = \mathrm{C}$

1 kcal = $\frac{\mathrm{x}}{0.002} = \mathrm{D}$

Thus, B < C < A < D