At 25 °c, what is the hydroxide ion concentration, [oh–], in an aqueous solution with a hydrogen ion concentration of [h ] = 3.0 × 10–5 m?

As,

Water has a pkw=14

so it can be represented as,

[H+] [OH-] = 1*10^-14

If [H+] = 3*10^-5M

[OH-] = (1*10^-14) / ( 3*10^-5)

[OH-] = 3.3*10^-9 M

answer; i believe the correct answer is (solid gold);

the answer is true.