Determine the pH of each solution. a. 0.0650 M HNO₃ b. 0.150 M HNO₂ c. 0.0195 M KOH d. 0.245 M CH₃NH₃I e. 0.318 M KC₆H₅O

The pH scale measures the acidity or basicity of a solution, ranging from 0 to 14. A pH less than 7 indicates an acidic solution, while a pH greater than 7 indicates a basic solution. A pH of 7 is considered neutral. The scale is logarithmic, meaning each whole number change represents a tenfold change in hydrogen ion concentration.

Strong acids, like HNO3, completely dissociate in water, contributing all their hydrogen ions to the solution, while weak acids, like HNO2, only partially dissociate. Similarly, strong bases, such as KOH, fully dissociate to provide hydroxide ions, whereas weak bases, like CH3NH3, do not fully dissociate. Understanding the strength of acids and bases is crucial for calculating pH accurately.

The concentration of hydrogen ions in a solution directly affects its pH. For strong acids, the pH can be calculated directly from the molarity of the acid, while for weak acids, the pH requires the use of the acid dissociation constant (Ka) to determine the concentration of hydrogen ions. For bases, the pOH can be calculated first, and then converted to pH using the relationship pH + pOH = 14.