Chapter 9: Q13P (page 208)

Barbituric acid dissociates as follows:
(b)Calculate the pH and fraction of dissociation of 10^-10.00 M barbituric acid.

Short Answer

Expert verified

The $pH of 10^{- 10.00} M is 7$

The fraction of disassociation is 99.9%

Step by step solution

Step 1 : Definition of pH.

pH is defined as a quantitative measure of acidity and basicity. Compounds having pH more than 7 is acidic in nature while when shown above than 7 is basic in nature. When pH comes 7 , compound is said to be neutral.

Step 2 : Calculate pH and fraction of dissociation.

Since the solution is highly diluted, we can consider that $pH = 7 ([H^{+}] = 10^{- 7})$ .

We will calculate the fraction of dissociation by:

$K_{a} = \frac{[H^{+}] [A^{-}]}{[HA]} [A^{-}] = \frac{K_{a}}{[H^{+}]} \times [HA] = \frac{9.8 \times 10^{- 5}}{10^{- 7}} \times [HA] [A^{-}] = 980 [HA]$

Step 3 : Calculate fraction of dissociation.

Now, using the same reaction, we will find fraction of dissociation:

$a = \frac{[A^{-}]}{[HA] + [A^{-}]} = \frac{980 [HA]}{[HA] + 980 [HA]} = 980 / 981 = 99.9 %$

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Barbituric acid dissociates as follows:
(b)Calculate the pH and fraction of dissociation of 10^-10.00 M barbituric acid.

Short Answer

Step by step solution

Step 1 : Definition of pH.

Step 2 : Calculate pH and fraction of dissociation.

Step 3 : Calculate fraction of dissociation.

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Barbituric acid dissociates as follows:(b)Calculate the pH and fraction of dissociation of 10-10.00 M barbituric acid.

Short Answer

Step by step solution

Step 1 : Definition of pH.

Step 2 : Calculate pH and fraction of dissociation.

Step 3 : Calculate fraction of dissociation.

One App. One Place for Learning.

Most popular questions from this chapter

Recommended explanations on Chemistry Textbooks

The Earths Atmosphere

Ionic and Molecular Compounds

Making Measurements

Organic Chemistry

Physical Chemistry

Chemistry Branches

Study anywhere. Anytime. Across all devices.

Barbituric acid dissociates as follows:
(b)Calculate the pH and fraction of dissociation of 10^-10.00 M barbituric acid.