Обчислення pH для сильних розчинів кислот/основ

Well first, we need to know what strong acids and strong bases are. A strong acid, or base, completely dissociates into its respective ions (protons and anions) in an aqueous solution.

Strong acids and bases react very quickly and successfully. The success of these reactions is due to the increased amount of ions in the solution; the more ions that are within a solution, the more likely collisions are to occur between atoms that push a reaction forward. Strong acids and bases always have more ions in solution due to their complete dissociation.

The pH scale is a range from 0 to 14, where zero represents the strongest acid and 14 represents the weakest acid. All acids can be ranked on this scale by taking into account the molar concentration of protons.

The acidity of a solution is based on the amount of protons ($H^{+}$) in the solution, also known as the hydrogen ion concentration. For example, some acids are: $HCl$, $H_{2}$$SO_{4}$, $NH_{4}Cl$, $HNO_{3}$. All of these compounds, when in an aqueous solution, dissociate into their respective ions and contribute a varying amount of [$H^{+}$]. We can use these properties when finding the pH of a solution in the laboratory.

If we know a pH of zero is the strongest acid, there must be the most concentrated amount of $H^{+}$ ions there, right? Yes!

This can be shown through the equation for pH:

$$pH=-log[H^{+}]$$

by manipulating this equation, we can see how a higher pH affects the concentration of protons: $$-pH=log[H]$$

$$10^{-pH}=[H]$$

The larger the pH gets, the more the decimal place moves to the left, decreasing our proton concentration, and indicating that the solution in question is decreasingly acidic. In other words, weaker acids will be further away from zero.

References: 1

(Video) 16.4 pH Calculations for Strong Acids and Bases | General Chemistry

by Chad's Prep

In this video, Chad explains how to calculate the pH of strong acids and bases. He runs through six example problems. He also highlights some common mistakes and tricks. This video will help you master pH calculations!