Answer:
a) Acidic buffer
b) No buffer
c) Acidic buffer
d) Basic buffer
e) Basic buffer
Explanation:
a) 75.0 mL of 0.10 M HF ; 55.0 mL of 0.15 M NaF
-Acidic buffer
Mixing of 75.0 mL of 0.10 HF and 55.0 mL of 0.15 mL NaF results in acidic buffer. HF/NaF is a buffer of weak acid and its conjugate base. F- is the conjugate base of acid,HF.
b.) 150.0 mL of 0.10 M HF ; 135.0 mL of 0.175 M HCl-No buffer
Mixing HF and HCl will not results in a buffer. Both are acids, and no conjugate base is present.
c.) 165.0 mL of 0.10 M HF ; 135.0 mL of 0.050 M KOH-Acidic buffer
HF reacts with KOH to form KF. F- is a conjujate base of HF. As volume and concentration of HF is more than KOH, therefore, HF will remain after reaction with KOH. HF/KF will be a buffer of weak acid and its conjugate base.
d.) 125.0 mL of 0.15 M CH3NH2 ; 120.0 mL of 0.25 M CH3NH3Cl -Basic buffer
CH3NH2/CH3NH3+ is a buffer of weak base and its conjugate acid.
e.) 105.0 mL of 0.15 M CH3NH2 ; 95.0 mL of 0.10 M HCl-Basic buffer
CH3NH2 is a weak base and HCl is a strong acid. CH3NH2 reacts with HCl to form its conjugate acid CH3NH3+. Volume and concentration of CH3NH2 is more as compared to HCl and hence, will remain in the soution after reactionf with HCl.
CH3NH3+/CH3NH2 is a buffer of weak base and its conjugate acid.
