An insulator container contains `4` moles of an ideal diatomic gas at temperature T. Heat Q is supplied to this gas, due to which `2` moles of the gas are dissociated into atoms but temperature of the gas remains constant. Then

Options

A. Q = 2 RT
B. Q = RT
C. Q = 3 RT
D. Q = 4 RT

Answer

B

Explanation

`Q = DeltaU = U​_f – U_(i)` = [internal energy of 4 moles of a monoatomic gas + internal energy of 2 moles of a diatomic gas] – [internal energy of 4 moles of a diatomic gas]
`=(4xx3/2"RT"+2xx5/2"RT")-(4xx5/2"RT")=RT`