Solution.
"HClO + OH^- = H2O + ClO^-"
"n(HClO(init)) = 0.05 \\times 1.0 = 0.05 \\ mol"
"n(NaOH(init)) = 0 \\ mol"
"n(ClO^-(init)) = 0 \\ mol"
Once we have added a certain amount of alkali, the amounts of substances will be as follows:
"n(HClO(fin)) = 0.05 - x \\ mol"
"n(NaOH(fin)) = x \\ mol"
"n(ClO^-(fin)) = x \\ mol"
Let us use the Henderson-hasselbach equation:
"pH = pKa + lg(\\frac{[ClO^-]}{[HClO]})"
"pKa = -lg(Ka) = 7.46"
"8.00 = 7.46 + lg(\\frac{x}{0.05-x})"
"3.47 = \\frac{x}{0.05-x}"
x = 0.039 mol
"C = \\frac{n}{V}"
"V = \\frac{n}{C}"
"V = \\frac{0.039}{0.01} = 3.9 \\ L"
Answer:
V(NaOH) = 3.9 L
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