Hydrogen and hydroxide ion concentration

[redfox]

Please help if you can. I've read and re-read thru instructions for doing this equation, but I'm still stumped:(

 

At 25 degreesC 0.212g of Barium Hydroxide Ba(OH)2 is dissolved completely in sufficient water to make .25 litres of final solution. I need to find the hydroxide ion and hydrogen ion concentrations. So far I have come up with...

 

molar mass of Ba(OH)2 = 171.02

.212/171.02 = 0.00124 mol/ .25 litre

=.00496 mol/ litre

 

so the Hydroxide (OH-) Right? should be .006232

but this is more than the whole amount, so how is it possible? And since Hydrogen ion is supposed to make up the rest of it, it would have to be a negative amount and...well...you see my problem. Is there any hope?