A compound '$\mathrm{X}$' when treated with phthalic anhydride in presence of concentrated $\mathrm{H}_{2} \mathrm{SO}_{4}$ yields '$\mathrm{Y}$'. '$\mathrm{Y}$' is used as an acid/base indicator. '$\mathrm{X}$' and '$\mathrm{Y}$' are respectively