1. Use the Henderson-Hasselbalch equation to calculate the pH of a solution that is 0.195 M in C2H5NH2 and 0.155 M in C2H5NH3Br.
Express your answer using two decimal places.

pH = ? (I entered 10.79 and there was a message that Not quite. Check through your calculations; you may have made a rounding error or used the wrong number of significant figures.)

2. Use the Henderson-Hasselbalch equation to calculate the pH of a solution that is 12.5 g of HC2H3O2 and 13.5 g of NaC2H3O2 in 150.0 ml of solution.
Express your answer using two decimal places.

pH = ?

A 100.0 -ml buffer solution is 0.110 M in NH3 and 0.135 M in NH4Br.

3. What mass of HCl could this buffer neutralize before pH the fell below 9.00?
Express your answer using two significant figures.

m = ?

4. If the same volume of the buffer were 0.260 M in NH3 and 0.390 M in NH4Br, what mass of HCl could be handled before the pH fell below 9.00?
Express your answer using two significant figures.

m = ?