Calculate pOH

[sarahtang4B]

When we calculate pOH for Ba(OH)2, why do we multiply the concentration by two?

Is it because there's two OH?

[Rimsha Hussaini 1A]

To put it simply, yes.

The chemical equation of the dissociation of Ba(OH)2 is Ba(OH)2 -> 2OH- + Ba2+
This indicates that in the dissociation of Ba(OH)2, 2 hydroxide ions form.

[Katie Sy 1L]

yes because of the 2 hydroxide ions

[EllerySchlingmann1E]

You have to multiply the concentration by two because of the molar ratio between Ba(OH)2 and hydroxide ions. If you don't recognize the difference in moles, your calculation and pH will be way off. Another reason why it's so important to have a balanced reaction before your start making any assumptions or calculations.