Answer:
Chemistry
Step-by-step explanation:
The pair that cannot be mixed together to form a buffer solution is:
RBOH and HBr
In order to form a buffer solution, we need a weak acid and its corresponding conjugate base or a weak base and its corresponding conjugate acid. The pair of substances should be able to resist changes in pH upon addition of small amounts of an acid or a base.
Out of the given pairs, the first four pairs can form buffer solutions:
- NH3 and NH4Cl can form a buffer solution as NH3 is a weak base and NH4+ is its corresponding conjugate acid.
- KOH and HF cannot form a buffer solution as KOH is a strong base and HF is a weak acid.
- NaCH3COO and HCl can form a buffer solution as CH3COO- is a weak base and CH3COOH is its corresponding conjugate acid.
- H3PO4 and KH2PO4 can form a buffer solution as H2PO4- is a weak acid and HPO42- is its corresponding conjugate base.
However, RBOH (rubidium hydroxide) is a strong base and HBr (hydrobromic acid) is a strong acid. They cannot form a buffer solution as there is no weak acid or weak base in the pair.