Which one among the following is the correct option for the relationship between $C_{P}$ and $C_{V}$ for one mole of an ideal gas?

Calculate the work done in joule if $2 \ mol$ of an ideal gas expands isothermally from $15.5 \ dm^3$ to $20 \ dm^3$ at a constant external pressure of $1 \ atm$. (in $J$)

The work done in an isothermal reversible process for an ideal gas is-

Calculate the work done in the following reaction at $300 \ K$ and at constant pressure. $(R = 8.314 \ J \ K^{-1} \ mol^{-1})$ $4 \ HCl_{(g)} + O_{2_{(g)}} \rightarrow 2 \ Cl_{2_{(g)}} + 2 \ H_2O_{(g)}$ (in $J$)

An ideal gas expands from $1 \times 10^{-3} \ m^{3}$ to $1 \times 10^{-2} \ m^{3}$ at $300 \ K$ against a constant external pressure of $1 \times 10^{5} \ Nm^{-2}$. The work done is:

Calculate the work done in joule if $1 \ mole$ of an ideal gas is compressed from volume $24 \ dm^3$ to $13 \ dm^3$ at a constant external pressure of $3 \ bar$. (in $J$)