Final answer:
When pH is higher than pKa, the substance exists in its unprotonated form due to the higher concentration of hydroxide ions in the solution which deprotonates the acid.
Step-by-step explanation:
When the43901096This is because the pKa value represents the pH at which half of the substance is in the protonated form (with an extra proton) and half is in the unprotonated form (without the extra proton).
When the pH exceeds the pKa, there is a higher concentration of hydroxide ions (OH-) in the solution, implying there's sufficient base present to deprotonate the acid, hence they exist mostly in their unprotonated or ionized forms.