A solution is prepared by adding 0.01 M acetic acid and 0 .01 M ethylamine to water and adjusting the pH to 7.4. What is the ratio of acetate to acetic acid? What is the ratio of ethylamine to ethylammonium ion?

Answer :

(a) The ratio of acetate to acetic acid is,

(b) The ratio of ethylamine to ethylammonium ion is,

Explanation :

Part (a) :

Using Henderson Hesselbach equation :

Given:

for acetic acid = 4.75

pH = 7.4

Now put all the given values in this expression, we get:

Thus, the ratio of acetate to acetic acid is,

Part (b) :

Using Henderson Hesselbach equation :

Given:

for ethylamine = 10.81

pH = 7.4

Now put all the given values in this expression, we get:

Thus, the ratio of ethylamine to ethylammonium ion is,