Calculating pH of a Buffer Solution with Added Sodium Hydroxide

[moephysics]

Homework Statement

A pH 9.56 buffer was prepared by mixing 2.00 moles of
ammonia and 1.00 moles of ammonium chloride in water
to form a solution with a volume of 1.00L.
To a 200 mL aliquot of this solution was added 10.0 mL of
10.0 M sodium hydroxide. What was the resulting pH?

Homework Equations

M(molarity)=n/v
pH(for buffers)=pKa+log[A-]/[CB+]

The Attempt at a Solution

I tried to make an ice table in order to calculate the final values of concentration but was unsuccessful. I've been giving the answerto the problem and I know how the second part was calculated.
" NH4+ + OH- (g)  NH3 (g) + H2O(l)
i. 0.952 M 0.476 M 1.905 M
C. -0.476 M -0.476 M +0.476 M
Comp 0.476 0 2.38 M
pH = pKa+ log[NH3]
[NH4
+]= −log(1.0×10−14/
1.8×10−5)+ log(2.38M)
(0.476M)= 9.95"
However I have no idea how to there, your help is much appreciated. Thankyou.

 

[Borek]

Don't solve buffer questions using ICE table, use Henderson-Hasselbalch equation.