What is the pH of a solition that is 1M in each of monobasic and dibasic...

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Question

What is the pH of a solition that is 1M in each of monobasic and dibasic sodium phosphate?

science chemistry

Answer 1

Answer #1

monobasic sodium phosphate NaH₂PO₄ is the weak acid.

dibasic sodium phosphate Na₂HPO₄ is the conjugate base.

K_a = 6.2 x 10^-8

pK_a = -log(K_a)

pK_a = -log(6.2 x 10^-8)

pK_a = 7.2

According to Henderson - Hasselbalch equation,

pH = pK_a + log([conjugate base] / [weak acid])

pH = pK_a + log([Na₂HPO₄] / [NaH₂PO₄])

pH = 7.2 + log(1 M / 1 M)

pH = 7.2 + log(1)

pH = 7.2 + 0

pH = 7.2

pH of solution is 7.2

Answer 2

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