Question

A 10â6 M HCl solution is diluted to 100 times. The pH of the diluted solution would be
(1) between 6 to 7
(2) between 7 to 8
(3) equal to 7
(4) equal to 10

Answer 1

A solution with pH 6 has concentration 10-6 M
If it is diluted 1000 times, it becomes 10-6/1000 = 10-9 M

Water has a pH = 7. Thus, [H3O+] in water = 10-7 M

Now, the [H3O+] in dilute acidic solution will approach 10-7 M. The concentration can not become less than 10-7 M due to dissociation of water to H3O+.
So, pH of resulting solution will be approx. 6.96.
option a is answer