Which of the following formulae is wrong?

Let $\gamma_1$ be the ratio of molar specific heat at constant pressure and molar specific heat at constant volume of a mono-atomic gas and $\gamma_2$ be the similar ratio of a diatomic gas. Considering the diatomic gas molecule as a rigid rotator, the ratio $\gamma_1/\gamma_2$ is

If for a gas $\frac{R}{C_V} = 0.67$,then the gas is .......

For hydrogen gas $(H_2)$,$C_P - C_V = a$,and for oxygen gas $(O_2)$,$C_P - C_V = b$. What is the relationship between $a$ and $b$?

Using the law of equipartition of energy, the specific heat (in $J\, kg^{-1}\, K^{-1}$) of aluminium at room temperature can be estimated to be (atomic weight of aluminium $= 27$).

$310 \ J$ of heat is required to raise the temperature of $2 \ moles$ of an ideal gas at constant pressure from $25 \ ^oC$ to $35 \ ^oC$. The amount of heat required to raise the temperature of the gas through the same range at constant volume is $.... \ J$.