which of the following could represent the pH of a strong base?

a. [H3O+]=1x10-2
b. [OH-]=1x10-2
c. [H3O+]=1x10-7
d. [H3O+]=1x10-12

1 answer

To determine which of the options could represent the pH of a strong base, we should first recall what pH and pOH represent and the relationship between [H3O+] and [OH].

  1. pH Scale: Ranges from 0 to 14. A pH less than 7 indicates an acid, a pH of 7 indicates neutrality, and a pH greater than 7 indicates a base.

  2. Relationship: [H3O+] and [OH] are related through the ion product of water (Kw): Kw=[H3O+][OH]=1.0×1014 From this, if you know [H3O+], you can find [OH] and vice versa.

Now, let's evaluate each option:

a. [H3O+]=1×102

pH=log(1×102)=2 This is strongly acidic.

b. [OH]=1×102

[H3O+]=Kw[OH]=1.0×10141.0×102=1.0×1012 pH=14pOH=14(log(1×102))=142=12 This is basic.

c. [H3O+]=1×107

pH=log(1×107)=7 This is neutral.

d. [H3O+]=1×1012

pH=log(1×1012)=12 This is also basic.

Thus, the options that could represent the pH of a strong base are:

  • b. [OH]=1×102 (pH = 12)
  • d. [H3O+]=1×1012 (pH = 12)

Both b and d represent the pH of a strong base.