Question

if you add 1.0 ml of 6.0 Molar HCl to 150.0 mL of acetate buffer

a.-calculate the pH if you add this acid to water

b.-which way does the buffer equilibrium reaction shift

c.- what happens to the concentration of A-

d.- what happens to the concentration of HA

e.-how many moles of protons are added to the buffer

Answer 1

a)
to how much water we added assume 150 mL water

calculate the concentration of HCl

M1V2 = M2V2

M2 = (6.0 x 1.0) / 151 = 0.04 M

pH = -log [H⁺]

pH = -log [0.04]

pH = 1.4

b) by adding HCl equilibrium shifts backwards due to more H⁺  ions added

c) A^-   + H⁺   --------> HA

some of A^- converted to HA

so A^- concentration will decrease

d) A^-   + H⁺   --------> HA

HA concentration will increase

e) n = M x V in L

n = 6.0 x 1.0 /1000

n = 0.006

moles of protons = 0.006 M