Final answer:
The statement suggesting pH as a common expression for corrosives is misleading because, while pH can indicate potential corrosiveness, it alone doesn't determine a substance's ability to corrode. pH indicates acidity or basicity, with strong acids and bases being potentially corrosive. Both strong acids and bases can cause harm due to their corrosive properties.
Step-by-step explanation:
The question about pH as a common expression for corrosives can be analyzed as follows. pH is indeed used to describe the acidity or basicity of a substance, which can indicate its corrosive potential. A substance is considered corrosive if it can dissolve or wear away other materials. However, pH by itself does not determine corrosiveness; it's one of the factors that can contribute to a substance's corrosive properties. For instance, strong acids and strong bases have extreme pH values and are generally more corrosive.
Acidity is measured on a scale known as the pH scale, which ranges from 0 to 14. A substance with a pH less than 7 is acidic, and one with a pH greater than 7 is basic (or alkaline). Pure water is neutral with a pH of 7. The pH measures the concentration of hydrogen ions (H+) in a solution. The lower the pH, the higher the concentration of hydrogen ions, and vice versa.
Acids and bases are defined by their ability to donate hydronium ions (H3O+) and hydroxide ions (OH−), respectively. Acids have a pH lower than 7 and taste sour, while bases have a pH higher than 7 and feel slippery. For example, battery acid has a very low pH, while lye, used in soap making, has a very high pH.
Contrary to the statement, both strong acids and strong bases can be harmful, not just acids. Strong bases are also corrosive and can cause burns, so it is false that they are gentle and cannot hurt you. The statement that 'The lower the pH, the higher the concentration of hydronium ions' is true.
Regarding the pH of hydrochloric acid, this is a very strong acid with a low pH, usually around 1 to 2. It's the acid secreted by our stomach lining to aid in digestion.