Solution:Concept- A weak acid and the conjugate base of the weak acid, or a weak base and the conjugate acid of the weak base, are combined to form the buffer solution, a water-based solvent solution. They don't change their pH when diluted or when small amounts of acid or alkali are added to them.
An acid and base conjugate pair, NaH2PO4 and Na2HPO4, make up the buffer solution. They will function admirably as buffers.
A weak acid and its conjugate base, or vice versa, are combined to form a buffer solution in water.
The pH of buffer solutions does not change when an acidic or basic component is added.
and are acid salts so they can act as acid as well as salt. When one acts as acid and other as salt they will form a buffer and their can be calculated by formula.
Hence, the correct answer is option (1).