# In terms of pK_a, which acid will be stronger? How does pK_a relate to pK_b?

Jul 5, 2017

$p H \equiv - {\log}_{10} \left[{H}_{3} {O}^{+}\right]$, and thus bases, and then weaker acids will have the NUMERICALLY higher $p H$........

#### Explanation:

$\text{For example 1}$, the weaker acid will have the higher $p H$.

$\text{For example 2}$, the weaker acid will have the higher $p H$; the acid whose ${K}_{a} = 8 \times {10}^{-} 6$.

$\text{For example 3}$, the stronger BASE will have the SMALLER $p {K}_{b}$, and thus the base with $p {K}_{B} = 4.5$ will give rise to the GREATER $\left[H {O}^{-}\right]$ conc..........

We recall (i) that $p H = - {\log}_{10} \left[{H}_{3} {O}^{+}\right]$,

and that $p O H = - {\log}_{10} \left[H {O}^{-}\right]$.

And (ii) in aqueous solution under standard conditions, $p H + p O H = 14$.......just as under these conditions $p {K}_{a} + p {K}_{b} = 14$. The stronger the acid, the weaker the conjugate base, and vice versa.

Jul 5, 2017
1. .1 M of a weak acid
2 . Ka = $8 \times 10 - 6$
2. pKb = $4.5$

#### Explanation:

Acid have a low pH the stronger the acid the lower the pH.
Bases have a high pH the strong the base the higher the pH.

1. The .1 Molar solution of weak acid will have a higher pH than a strong acid.

2. The Ka of ${10}^{-} 6$ will be a weaker acid than one with a Ka of $2 \times {10}^{-} 3$ so have a higher pH.

3. The pkb of 4.5 is stronger than than a base with a pkb of 6.5.
so the pkb of 4.5 will have a higher pH.