Which of the following is not equal to zero for an ideal solution?

Which of the following will form an ideal solution?

Two liquids $X$ and $Y$ form an ideal solution. At $300 \ K,$ vapour pressure of the solution containing $1 \ mol$ of $X$ and $3 \ mol$ of $Y$ is $550 \ mm \ Hg.$ At the same temperature,if $1 \ mol$ of $Y$ is further added to this solution,vapour pressure of the solution increases by $10 \ mm \ Hg.$ Vapour pressure (in $mm \ Hg$) of $X$ and $Y$ in their pure states will be,respectively:

Total vapour pressure of a mixture of $1 \, mol \, X$ $(P_x^o = 150 \, torr)$ and $2 \, mol \, Y$ $(P_y^o = 300 \, torr)$ is $240 \, torr$. In this case:

An aqueous solution of hydrochloric acid:

For which of the following liquid mixtures $\Delta_{\text{mix}}H=0$ and $\Delta_{\text{mix}}V=0$?