HendersonHasselbalch
posted by Kyle on .
If the same volume (130mL) of the buffer were 0.265 M in NH3 and 0.400 M in NH4Br, what mass of HCl could be handled before the pH fell below 9.00?
I used the hendersonhasselbalch equation to solve this. i set it up as 9=9.24551+log((0.03445x)/(0.052+x))
0.03445= moles of NH3
0.052= moles of NH4Br
I calculated the grams to be .11 g but it was wrong. Did i set up my HH equation wrong?

Assistance needed.
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See above for my response.

The x is small approximation doesn't work for this problem, so you have to set up an ICE table to solve for the amount of HCl, you can't use the HH