In which solution,the solubility of the solute decreases with an increase in temperature?

In which of the following salts,the solubility increases appreciably with an increase in temperature?

Henry's law constant for the molality of methane in benzene at $298 \, K$ is $4.27 \times 10^{5} \, mm \, Hg$. Calculate the solubility of methane in benzene at $298 \, K$ under $760 \, mm \, Hg$.

Calculate the quantity of $CO_2$ required to prepare $1 \,L$ of soda water when the soda water is packed under $2 \,atm$ of $CO_2$. [Henry's law constant for $CO_2$ is $1.67 \times 10^8 \,Pa$] (in $\,g$)

Which of the following gases is least soluble in water at the same temperature and pressure?

$5.5 \text{ mg}$ of nitrogen gas dissolves in $180 \text{ g}$ of water at $273 \text{ K}$ and $1 \text{ atm}$ pressure due to nitrogen gas. The mole fraction of nitrogen in $180 \text{ g}$ of water at $5 \text{ atm}$ nitrogen pressure is approximately: