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Topic: Weak Acid plus Strong Base pH  (Read 4950 times)

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Offline yankeekd25

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Weak Acid plus Strong Base pH
« on: March 29, 2009, 09:00:55 PM »
An aqueous solution contains 0.434 M hydrocyanic acid.

Calculate the pH of the solution after the addition of 3.20E-2 moles of sodium hydroxide to 150 mL of this solution.
(Assume that the volume does not change upon adding sodium hydroxide).

Ka for HCN= 4.0 x 10^-10

Doesn't the concentration of the conjugate base need to be given in order to solve this?
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Offline Borek

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Re: Weak Acid plus Strong Base pH
« Reply #1 on: March 30, 2009, 03:34:30 AM »
Quote from: yankeekd25 on March 29, 2009, 09:00:55 PM
Doesn't the concentration of the conjugate base need to be given in order to solve this?

You have to calculate it. Assume neutralization went to completion.
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Offline yankeekd25

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Re: Weak Acid plus Strong Base pH
« Reply #2 on: March 30, 2009, 08:56:43 AM »
Okay. How do you calculate it?
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Offline AWK

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Re: Weak Acid plus Strong Base pH
« Reply #3 on: March 30, 2009, 11:03:12 AM »
Start from a balanced equation of neutralization
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