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11/10/2021 3:32 pm
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A solution of 0.1 M NaZ has pH = 8.90. The Ka of HZ is
(a) 6.3 × 10-11
(b) 6.3 × 10-10
(c) 1.6 × 10-5
(d) 1.6 × 10-6
1 Answer
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11/10/2021 3:37 pm
Correct answer: (c) 1.6 × 10-5
Explanation:
NaZ is salt of WA/SB
∴ pH = \(\frac{1}{2}\)(pKw + pKa + logC)
8.9 x 2 = 14 + pKa + log0.1
17.8 = 14 + pKa - 1
pKa = 4.8
Ka = Antilog(-4.8)
= 1.585 x 10-5 = 1.6 x 10-5