Chemistry - GOC Question with Solution | TestHub

${\mathrm{pK}}_{\mathrm{a}}$ = −${\log }_{10}$ ${\mathrm{K}}_{\mathrm{a}}$, so a smaller ${\mathrm{pK}}_{\mathrm{a}}$ means a larger ionization constant and a stronger acid. With the stated values, ${\mathrm{K}}_{\mathrm{a}}$(y)/${\mathrm{K}}_{\mathrm{a}}$(x) = $10^{1.5-0.88}$ ≈ 4.2. Hence y has the larger first-ionization constant and ${\mathrm{pK}}_{\mathrm{a}1}$(x) > ${\mathrm{pK}}_{\mathrm{a}1}$(y); A is correct. The keto drawing of y belongs to the semisquaric tautomeric system, whose conjugate base delocalizes charge onto the oxygen-containing framework.