# What is the hydroxide ion concentration, [OH-], in an aqueous solution with a hydrogen ion...

## Question:

What is the hydroxide ion concentration, {eq}[OH^-] {/eq}, in an aqueous solution with a hydrogen ion concentration of {eq}[H^+]=3.5 \times 10^{-3} M {/eq} ?

## The Water Autoionization Constant:

Kw, the water autoionization constant, is the relationship between {eq}OH^- {/eq} and {eq}H^+ {/eq} in solution. Kw is equal to {eq}1.0 \times 10^{-14} {/eq}.

You might be wondering why I'm talking about water autoionization when the problem above is asking about the hydroxide ion concentration. Well, Kw is useful for calculating the concentrations of {eq}OH^- {/eq} and {eq}H^+ {/eq} in solution because:

$$K_w= [H^+] \times [OH^-]$$

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We will use the formula for Kw to solve this problem. We have been given the hydrogen ion concentration, {eq}3.5 \times 10^{-3} M {/eq}, and we know...

Hydroxide Ion: Definition & Formula

from

Chapter 28 / Lesson 44
25K

If the name 'hydroxide' sounds toxic to you, that's good. Hydroxide is a powerful chemical with potentially dangerous properties. Learn the definition and formula of hydroxide, as well as some interesting facts about it, in this lesson.