Problem: Which weak acid would be best to use when preparing a buffer solution with a pH of 9.90? a) An acid with Ka = 7.9 times 10-12 b) An acid with Ka = 2.0 times 10-5 c) An acid with Ka = 2.5 times 10-7 d) An acid with Ka = 1.6 times 10-6 e) An acid with Ka = 2.0 times10-8 f) An acid with Ka = 1.3 times 10-10

FREE Expert Solution

buffer → pKa of acid must be near on the desired pH

pKa = -log(Ka)

a. 7.9x10-12 = 11.10

b. 2.0x10-5 = 4.70

View Complete Written Solution
Problem Details

Which weak acid would be best to use when preparing a buffer solution with a pH of 9.90? 

a) An acid with Ka = 7.9 times 10-12 

b) An acid with Ka = 2.0 times 10-5 

c) An acid with Ka = 2.5 times 10-7 

d) An acid with Ka = 1.6 times 10-6 

e) An acid with Ka = 2.0 times10-8 

f) An acid with Ka = 1.3 times 10-10

Frequently Asked Questions

What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the Buffer concept. You can view video lessons to learn Buffer. Or if you need more Buffer practice, you can also practice Buffer practice problems.