Asked by Lyca
Calculate the change in pH if 10mL of 0.1M HCl is added to the buffer made by mixing 25 mL of 1.0 M CH3COOH and 25 mL of 0.5 M CH3COONa.
Answers
Answered by
Devron
First, determine the number of moles for CH3COOH (HAc), CH3COONa (Ac^-), and HCl
Molarity=moles/Volume (L)
Moles=molarity*volume (L)
Moles of HCl=0.1M*0.010L=x
Moles of HAc=1.0M*0.025L=y
Moles of Ac^-=0.5M*0.025L=z
Calculate the pH of the buffer:
pH=pka+log[A^-/HA]
Where
pka=4.75
A^-=z
HA=y
and
pH=???
Solve for pH:
pH=4.75+log[z/y]
When HCl is added to the solution, HAc will increase and Ac^- will decrease.
Solve for the amount of change:
y+x=y1
z-x=z1
Use the Henderson-Hasselbalch equation and solve for the pH:
pH=4.75+log[y1/z1]
Subtract the pH of the buffer after addition of HCl from the pH of the buffer after addition of HCl.
Molarity=moles/Volume (L)
Moles=molarity*volume (L)
Moles of HCl=0.1M*0.010L=x
Moles of HAc=1.0M*0.025L=y
Moles of Ac^-=0.5M*0.025L=z
Calculate the pH of the buffer:
pH=pka+log[A^-/HA]
Where
pka=4.75
A^-=z
HA=y
and
pH=???
Solve for pH:
pH=4.75+log[z/y]
When HCl is added to the solution, HAc will increase and Ac^- will decrease.
Solve for the amount of change:
y+x=y1
z-x=z1
Use the Henderson-Hasselbalch equation and solve for the pH:
pH=4.75+log[y1/z1]
Subtract the pH of the buffer after addition of HCl from the pH of the buffer after addition of HCl.
Answered by
lee chong wei
pH=4.66