List of practice Questions

Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R:
Assertion (A): B_eCl₂ and MgCl₂ produce characteristic flame. 
Reason (R) : The excitation energy is high in B_eCl₂ and MgCl₂ 
In the light of the above statements, choose the correct answer from the option given below

Two moles of an ideal monoatomic gas occupies a volume $V$ at $27^{\circ}C$. The gas expands adiabatically to a volume $2V$. Calculate $(a)$ the final temperature of the gas and $(b) $ change in its internal energy -