For a reaction : $2\mathrm{A}\left(\mathrm{g}\right)⟶\mathrm{B}\left(\mathrm{g}\right)$; $∆\mathrm{Hl}= - 40 \mathrm{kcal}$. If rate constant for disappearance of A is ${10}^{-2}{\mathrm{M}}^{-1}{\sec }^{-1}$ then identify the options which will be correct. [Assume gases to behave ideally and reaction to be occurring at 300 K] [Take : $\mathrm{R} = 2 \mathrm{cal}/\mathrm{mol} \mathrm{K}$]

The reaction must be an elementary reaction

Change in internal energy of the reaction will be -19. 7 kcal/mole of A consumed

The rate at which heat will be liberated initially when 2 moles of A is taken in 3 litre rigid vessel will be approx. 0.26 kcal/sec.

Time required for concentration of A to decrease from 1 M to 0.5 M will be 100 sec