K a of HCOOH is 1.8 × 1 0 − 4 and K b of NH 3 is 1.8 × 1 0 − 5 . The pH of an aqueous solution of ammonium formate is closest to:

For a salt of a weak acid and a weak base, pH = 7 + 2 1 ( p K a − p K b ) . p K a = 3.75 and p K b = 4.75 . pH = 7 + 0.5 × ( 3.75 − 4.75 ) = 6.5 . Answer: (A).

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Chemistry - Ionic Equilibrium Question with Solution | TestHub

ChemistryIonic EquilibriumHydrolysis of SaltsEasy2 minQB

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$K_{a}$ of $HCOOH$ is $1.8 \times 1 0^{- 4}$ and $K_{b}$ of $NH_{3}$ is $1.8 \times 1 0^{- 5}$ . The pH of an aqueous solution of ammonium formate is closest to:

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Answer:

Solution:

For a salt of a weak acid and a weak base, $pH = 7 + \frac{1}{2} (p K_{a} - p K_{b})$ .

$p K_{a} = 3.75$ and $p K_{b} = 4.75$ .

$pH = 7 + 0.5 \times (3.75 - 4.75) = 6.5$ .

Answer: (A).

Stream:JEESubject:ChemistryTopic:Ionic EquilibriumSubtopic:Hydrolysis of Salts

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