Question

Write the reaction explain the mechanism of action of ppp phosphate buffer when added to koh

Answer 1

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Answer:

Here's what these equations are.

Explanation:

A phosphate buffered saline (PBS) buffer usually contains the following species

Sodium chloride, NaCl ;Potassium chloride, KCl;Disodium phosphate, Na2HPO4 ;Monopotassium phosphate, KH2PO4

.

The two species thata give PBS its buffer capacity are the hydrogen phosphate, HPO2−4, and dihydrogen phosphate, H2PO−4 ions.

An equilibrium reaction is established between these two ions in solution, with dihydrogen phosphate acting as an acid, i.e. donating a proton, and hydrogen phosphate acting as a base, i.e. accepting a proton.

H2PO−(aq)acid+H2O(l)⇌HPO2−4(aq) conj base+H3O+(l) ...(1)

When a strong acid is added to the buffer, the excess hydronium ions will be consumed by the hydrogen phosphate ion

H3O+(aq+HPO2−4(aq)→H2PO−4(aq)+H2O(l)

The strong acid will thus be converted to a weak acid. Likewise, when a strong base is added, the excess hydroxide ions will be consumed by the dihydrogen phosphate ion.

OH−(aq)

+H2PO−4(aq)→HPO2−4(aq)+H2O(l)

The strongbase will thus be converted to a weak base.

In relation to equation (1) , you can say that

Excess hydronium ions will shift the equilibrium to the left;

Excess hydroxide ions will shift the equilibrium to the right.