A0.100 m solution of a monoprotic weak acid has a ph of 3.00. what is the pka of this acid?

Explanation:

It is known that the relation between pH and hydrogen ion concentration is as follows.

             pH =

                  3 =

                  antilog (-3) =

                      M

Now, let the given acid is HA and it dissociates as follows.

                  0.1           0         0

                0.1 - x         x         x

We know that relation between , and HA is as follows.

                    =

                     =

                  =

Also,    

                        =

                       = 5.00

Thus, we can conclude that the of given acid is 5.0.

5 structural isomers

the isomers are:

n-exane :   ch3ch2ch2ch2ch2ch3

2-methylpentane :   ch3ch(ch3)ch2ch2ch3

3-methylpentane :   ch3ch2ch(ch3)ch2ch3

2,3-dimethylbutane :   (ch3)2chch(ch3)2

2,2-dimethylbutane :   (ch3)3cch2ch3