#3.00x106^-3# mol of HBr are dissolvedin water to make 16.0 L of solution. What is the concentration of hydroxide ions, [OH-] in this solution?

1 Answer
Apr 17, 2017

Answer:

We use the relationship #pH+pOH=14# in aqueous solution.

Explanation:

Hydrogen bromide is conceived to dissociate entirely in aqueous solution:

#HBr stackrelcolor(blue)(H_2Ocolor(white)(X))(→) H_3O^(+) + Br^(-)#

And thus #[H_3O^+]="Moles of acid (mol)"/"Volume of solution (L)"#

#=(3.00xx10^-3*mol)/(16.0*L)=1.88xx10^-4*mol*L^-1.#

And so #pH=-log_10(1.88xx10^-4)=3.73#.

#pOH=14-3.73=10.27#

And thus #[HO^-]=10^(-10.27)*mol*L^-1=5.33xx10^-11*mol*L^-1#.