Question

What is the pH of baking soda?

Answer 1

As we know that in generally, pH value of all acids are in between ${\text{0}}{\text{.9}}$-$6.9$ and all the bases are in between$7.1 - 14.0$. The pH value of the substance depends on the concentration of hydrogen ions in the solution. The $pOH$ value of the substance depends on the concentration of hydroxyl ion in the solution. The pH value is directly proportional to the ${K_a}$ value and inversely proportional to $p{K_a}$ value of the solution. The pH value is directly proportional to the $p{K_b}$ value and inversely proportional to kb value of the solution. The $pOH$ value is directly proportional to the ${K_b}$ value and inversely proportional to $p{K_b}$ value of the solution. The $pOH$ value is directly proportional to the $p{K_a}$ value and inversely proportional to ${K_a}$ value of the solution.
The pH of the solution is
${\text{pH = 14 - pOH}}$
{\text{pH = 14 - }}\left\\{ {{\text{ - log}}\left[ {{\text{O}}{{\text{H}}^{\text{ - }}}} \right]} \right\\}
${\text{pH = 14 + log}}\left[ {{\text{O}}{{\text{H}}^{\text{ - }}}} \right]$

Complete answer:
We have to know that the baking soda is a base. The chemical name of baking soda is sodium bicarbonate. The chemical formula of baking soda is ${\text{NaHC}}{{\text{O}}_{\text{3}}}$.
Baking soda is a base, hence, the pH value is in between $7.1 - 14.0$.
The accurate pH value of baking soda is $9$.

Note:
We have to remember that Arrhenius is one of the concepts for acid and bases. Swedish chemist Arrhenius is the world's first chemist to talk about acid and bases. Depending on his concept and limitations later so many concepts are developed. Even Arrhenius is the birthplace of the concept of acids and bases. Followed by Arrhenius chemist the concept of acids and bases discuss Bronsted and Lowry in the world. But, Arrhenius theory has some limitations. One of the main limitations is not being able to explain the behaviour of acids and bases in non-aqueous solvents such as acetone etc,. It is not able to explain the acid which doesn't contain hydrogen and bases don’t contain hydroxyl ion in the formula. Ammonia is a well known base and is not accepted as base in Arrhenius base. These limitations are recovered by further coming theories like the Bronsted and Lowry concept of acids and bases.