Question

If a buffer solution is 0.210 M in a weak base (Kb = 4.9 × 10 − 5 M) and 0.480 M in its conjugate acid, what is the pH?

Answer 1

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0.210m in weak base Kb = 4.98165M 0.480m in conjugate acid Solution, from Ko, we can find pkb. pK6= -log (ko) - log (4.9x10-5) = -(-4:3) = 4.3 It is a weak base. so the buffer contains a solution a weak base and its conjugate acid. Using Henderson - Hasselbalch equation. poh = pk6+ log ( [conjugate a cid] [weak base] pOH = 4.3 + log ( 8.400 pOH = 4.3 + 0.35= 4.65 PH+ poH= 14 pH = 14-4.65 = 9.35