Question

Arrange the following compounds from strongest acid to weakest acid based on the provided K, values.

Answer 1

Understanding of \(\mathrm{K}_{\mathrm{a}}\) and \(\mathrm{pK}_{\mathrm{a}}\) :

A large \(\mathrm{K}_{\mathrm{a}}\) value indicates a strength of acid because it means the acid is largely dissociated into ions. A large \(\mathrm{K}_{\mathrm{a}}\) value also means the formation of products in the reaction is favored. A small \(\mathrm{K}_{\mathrm{a}}\) value means very

less ammount of the acid dissociates, so acid is weak. The \(\mathrm{K}_{\mathrm{a}}\) value for most weak acids ranges from \(10^{-2}\) to \(10^{-14}\).

The \(\mathrm{pK}_{\mathrm{a}}\) gives the same information about acidic strength but, just in a different way. The smaller the value of \(\mathrm{pK}_{\mathrm{a}}\), the stronger the acid. Weak acids have a \(\mathrm{pK}_{\mathrm{a}}\) ranging from \(2-14 .\)

Now come to the question, \(K_{a}\) values given as

1. \(2.30^{*} 10^{-13}-\) Weakest Acid

2. \(5.30 * 10^{-4}\)

3. \(5.90^{*} 10^{-2}\) - Strongest Acid

4. \(7.20^{*} 10^{-4}\)

as we know higher the \(\mathrm{k}_{\mathrm{a}}\) values stronger the acid so

acidic strength order is \((3)>(4)>(2)>(1)\)