Question

What is the difference between ${K_b}$ and $p{K_b}$.

Answer 1

$P{k_b}$ can be used to describe strength of bases, $p{K_b}$ is the negative base-10 logarithm of the base dissociation constant of a solution.
$p{K_b} = - \log 10{K_b}$

Complete step by step answer
As we know that the $p{K_b}$is the dissociation constant. We know that $p{K_b}$ is the negative base $10$ logarithm of the base dissociation constant $\left( {{K_b}} \right)$ of a solution. It is used to determine the strength of a base or an alkaline solution. The lower the $p{K_b}$value, the stronger the base. The base dissociation constant calculation is an approximation that is only accurate in dilute solution.
$\left( {{K_b}} \right)$ can be found using the following formula. ${K_b} = \dfrac{{\left[ {{B^ + }} \right]\left[ {O{H^ - }} \right]}}{{\left[ {BOH} \right]}}$
The above expression is obtained from the chemical equation: $\left( {B{H^ + }} \right) + \left( {O{H^ - }} \right) \to B + {H_2}O$
where,a pH of 0 is the most acidic with maximum hydronium ion concentration in water and 14 is the most alkaline having maximum hydroxyl ion concentration in water and pure water has a pH of 7 being completely neutral.
Acid and bases in water increases the concentration of the ions ${H^ + }$ and $O{H^ - }$ that from water. The dissociation constant of acid and base, called ${K_a}$ and ${K_b}$.
For acid, the relationship is shown by the expression, ${K_a} = \dfrac{{\left[ {{H_3}{O^ + }} \right]\left[ {{A^ - }} \right]}}{{\left[ {HA} \right]}}$.
Notice that water is not present in this expression. We get to ignore water because it is a liquid and we have no means of expressing its concentration. The dissociation constant of weak acid and weak bases, these are obtained by applying law of action on the ionic equilibria of weak acid and weak base. Value of dissociation constant of acids and bases are directly proportional to the acidic and basic strength of acids and bases.

Note:
The equilibrium that is formed between the unionized molecule and the ions which are present in the solution of weak electrolyte and the ions in the solution of weak electrolytes is called ionic equilibrium.