Which graph represents the relationship between heat capacity at constant pressure $(C_p)$ and temperature $(T)$ for a monatomic ideal gas?

$A$ piece of metal weighing $100 \, g$ is heated to $80^{\circ} C$ and dropped into $1 \, kg$ of cold water in an insulated container at $15^{\circ} C$. If the final temperature of the water in the container is $15.69^{\circ} C$,the specific heat of the metal in $J / g \cdot ^{\circ} C$ is

Specific heat capacity is defined as:

$A_{(g)} \to 2B_{(g)}$; $\Delta_rH = 20 \ kJ/mol$ at $300 \ K$. If $C_{p,m}(A) = 20 \ J \ K^{-1} \ mol^{-1}$ and $C_{p,m}(B) = 5 \ J \ K^{-1} \ mol^{-1}$,which of the following statements is correct?

The molar heat capacity of water at constant pressure is $75 \, J \, K^{-1} \, mol^{-1}$. When $1.0 \, kJ$ of heat is supplied to $100 \, g$ of water which is free to expand,the increase in temperature of water is (in $, K$)

When a $60 \, W$ electric heater is immersed in a gas for $100 \, s$ in a constant volume container with adiabatic walls,the temperature of the gas rises by $5^{\circ} \, C$. The heat capacity of the given gas is $......... \, J \, K^{-1}$ (Nearest integer).