Chemistry - Ionic Equilibrium Question with Solution | TestHub

ChemistryIonic EquilibriumpH of Strong and Weak Acids and BasesMedium2 minQB

ChemistryMediumsingle choice

A drug is a weak base whose conjugate acid has $p K_{a} = 6.0$ . The pH of gastric juice is about 2 and the pH of the small intestine is about 8. The drug will be:

Options:

Answer:

Solution:

For a base $B$ with conjugate acid $BH^{+}$ : $\frac{[ BH ^{+} ]}{[ B ]} = 1 0^{p K_{a} - pH}$ .

At pH 2: ratio $= 1 0^{4}$ , so almost entirely protonated (ionised).

At pH 8: ratio $= 1 0^{- 2}$ , so almost entirely the neutral base (unionised).

Answer: (C).

Stream:JEESubject:ChemistryTopic:Ionic EquilibriumSubtopic:pH of Strong and Weak Acids and Bases

⏱ 2mℹ️ Source: QB

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