Question

What is the pH of a $0.500M$ solution of acetyl salicylic acid, \[pK = 3.52\]?

Answer 1

Hint: We know that Dissociation constant $K_a$ is a quantitative proportion of the strength of an acid in solution. It is the balance steady for a substance response. It is otherwise called as
Otherwise called acidity constant or acid ionization constant.
The equation f an acid constant is as follows,
${K_a} = \dfrac{{\left[ {{A^ - }} \right]\left[ {{H^ + }} \right]}}{{\left[ {HA} \right]}}$
The $p{K_a}$ value can be calculated using the equation,
$p{K_a} = \log \dfrac{{\left[ {HA} \right]}}{{\left[ {{A^ - }} \right]\left[ {{H^ + }} \right]}}$

Complete answer:
We have to remember that the $p{K_a}$ esteem is one technique used to show the strength of an acid. $p{K_a}$ is the negative log of the acid separation steady or $k_a$ esteem. Lower $p{K_a}$ esteem shows a more grounded acid. That is, the lower esteem demonstrates the acid all the more completely separates in water.
The relationship between ph and $p{K_a}$ is,
\[pH = \dfrac{{p{K_a}\; + lo{g_{10}}\left[ {{A^ - }} \right]}}{{\left[ {AH} \right]}}\]
In case of weak acid pH can be calculated as,
$pH = \dfrac{1}{2}\left( {p{K_a} - \log a} \right)$
Here a is the concentration of an acid.
It is given that the pK value is \[3.52\].
The concentration of acid is \[0.5M\].
$pH = \dfrac{1}{2}\left( {3.52 - \log \left( {0.5} \right)} \right)$
$pH = \dfrac{1}{2}\left( {3.52 - \left( { - 0.301} \right)} \right)$
On simplification we get,
$pH = 1.91$
The pH of the solution is $1.91$.

Note:
We need to remember that the pH is defined as the quantitative proportion of the basicity and acidity of fluid. The term, broadly utilized in science, science, and agronomy, deciphers the upsides of the grouping of the hydrogen particle—which conventionally goes between around \[1\] and \[10 - 14\] gram-reciprocals per liter—into numbers somewhere in the range of \[0\] and \[14\]. In unadulterated water, which is impartial (neither acidic nor antacid), the convergence of the hydrogen particle is \[10 - 7\] gram-reciprocals per liter, which relates to a pH of \[7\] .Solution with a pH under \[7\] is considered acidic; Solution with a pH more prominent than \[7\] is viewed as fundamental, or basic.