InterviewSolution
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InterviewSolution
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An organic base X has Kb equal to 1 x 10-8 . In what amount should 0.01 M HCI and 0.01 M solution of X be mixed to prepare 1 litre of a buffer solution having pH 7? |
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Answer» Kb = 1 × 10−8 0 ∙ 01 M HCl, 0 ∙ 01 M of solution × (Base) Total volume = 1 litre pH = 7 ∙ 0, X+ H2O ⇌ XH+ + OH− Kb = \(\frac{[XH^+][OH^-]}{[X]}\) = 1 × 10−8 pOH = pKb + log\(\frac{[XH^+]}{[X]}\) 7 = − log 10−8 + log\(\frac{[XH^+]}{[X]}\) 7 = 8 + log\(\frac{[XH^+]}{[X]}\) log\(\frac{[XH^+]}{[X]}\) = -1 \(\frac{[XH^+]}{[X]}\) =10-1 = 0.1 Suppose volume of HCl taken is x l. Volume of base = (1 - x) l After the reaction base left = (1 - x - x) of 0.01 M XH+ formed = x L of 0 ∙ 01 M \(\frac{[XH^+]}{[X]}\)= \(\frac{x}{1-2x}\) = 0.1 x = 0 ∙ 083 Volume of HCl = 0 ∙ 083 L Volume of Bases = 0 ∙ 917 L |
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