Determine which of the solutions containing each of the following substances is a buffer. Check all that apply.

K3PO4 and K2HPO4
NaHCO3 and K2CO3

NH3 alone

NH4Cl and NH3

None of the above

X

1 answer

- K3PO4 and K2HPO4: These two substances can act as a buffer system as they both contain phosphate ions in different protonation states (H3PO4 and H2PO4-). A buffer system can be formed using a mixture of weak acid and its conjugate base.

- NaHCO3 and K2CO3: These two substances can also act as a buffer system as they both contain carbonate ions in different protonation states (HCO3- and CO3^2-). A buffer system can be formed using a mixture of weak acid and its conjugate base.

- NH3 alone: NH3 on its own cannot act as a buffer because it is a weak base, not a weak acid or its conjugate base.

- NH4Cl and NH3: This combination can act as a buffer system as NH4+ in NH4Cl can act as a weak acid and NH3 can act as its conjugate base.

Therefore, the solutions containing K3PO4 and K2HPO4, NaHCO3 and K2CO3, and NH4Cl and NH3 are buffers.