In which of the following oxides of three elements $X, Y$ and $Z$ are correctly arranged in the increasing order of acidic nature. The electronic configurations of $X, Y$ and $Z$ are $[\mathrm{Ne}] 3 s^2 3 p^1,[\mathrm{Ne}] 3 s^2 3 p^5$. [Ne] $3 s^2$ respectively

According to given electronic configuration, $X$ is $\mathrm{Al}, Y$ is $\mathrm{Cl}$ and $\mathrm{Z}$ is $\mathrm{Mg}$. Along a period, the basic nature of oxides decreases and acidic nature of oxides increases. $\mathrm{Mg}, \mathrm{Al}$ and $\mathrm{Cl}$ belong to same period with $\mathrm{Mg}$ on left side $\mathrm{f}$ the period, $\mathrm{Cl}$ on the right side and $\mathrm{Al}$ in between them. $\therefore$ Oxide of $\mathrm{Cl}$ is i.e. $Y$ will be most acidic oxide of $\mathrm{Mg}$, i.e. $\mathrm{Z}$ will be basic and oxide of $\mathrm{Al}$, i.e. $X$ in between the other two. $\therefore$ Correct increasing order acidic nature will be $Z < X < Y$