Question

CAN SOMEONE HELP ME!!

Solutions of each of the hypothetical acids in the following table are prepared with an initial concentration of 0.100 M. Which of the four solutions will have the lowest pH and be most acidic? Explain please.
Acid pKa
HA 4.00
HB 7.00
HC 10.00
HD 11.00
a. HA
b. HB
c. HC
d. HD
e. All will have the same pH because the concentrations are the same.

Answer 1

Answer: HA has lowest pH and it is the most acidic as compared to the rest of given acids.

Step-by-step explanation:

We know that relation between
`pK_a` and
`K_a` is as follows.

`pK_a = -log K_a`

This means that more is the value of
`K_a`, smaller will be the
`pK_a`. Also, more is the value of
`K_a` smaller will be the pH of a solution.

As, larger is the value of
`K_a` more negative will be the
`pK_a` value. Hence, stronger will be the acid.

In the given options, HA has the smallest
`pK_a` value.

Therefore, we can conclude that HA has lowest pH and it is the most acidic as compared to the rest of given acids.