Question

What is the pKa of $HC{{l}_{\left( aq \right)}}$ ?

Answer 1

We know that the pKa value is used to indicate the strength of an acid. It is found that pKa is the negative log of the Ka acid dissociation constant value or we can say acid dissociation constant. A lower value of pKa indicates a stronger acid.

Complete answer:
As we know that the pKa that pKa is the negative log of the Ka (acid dissociation constant) value. Acid strength can be defined as the tendency of an acid, to dissociate into a proton, and an anion, and symbolized by the formula HA. The dissociation of a robust acid in solution is effectively complete, except in its most concentrated solutions. Any acid with a pKa value which is a smaller amount than about $-2$ is classed as a robust acid. This results from the very high buffer capacity of solutions with a pH value of one or less and is understood because the leveling effect
So, if we see hydrochloric acid then it is chemically written as $HCl.$ Here, one H atom combines with one chlorine atom giving the molecule. We know that the octet of chlorine gets complete after sharing one electron with the Hydrogen atom. So, it has no tendency to accept more hydrogen atoms. But $HCl$ has one H atom which it can donate. So, it comes under the category of acids. Since, pKa value of $HC{{l}_{\left( aq \right)}}$ is $-8.08.$

Note:
Remember that the acids and bases can be differentiated on the basis of pKa value which is inversely proportional to ka value. The ka value is the dissociation constant. If pKa value is low, then ka value will be high and acid will be strong.