chemistry question 3

Question

An aqueous solution has [H3O+]=1.5x10^-12 M

a)determine [OH-] in M

b)determine the pH

c)explain if it is acidic, basic or neutral

please show work to help me :)

Answer 1

a)

Kw=[H3O+][OH-]

Kw=10^-14

10^-14=[1.5×10^-12][x]

x=[OH-]=6.7×10^-3 M

b)

pH=-log[H3O+]

pH=-log[1.5×10^-12]

pH=11.82

c)

Acidic because pH>7 and [OH-]>[H3O+]