A solution in which the pH is 1.5 would be described as:
Option 1: Slightly acidic.
Option 2: Very acidic.
Option 3: Slightly basic.
Option 4: Very basic.
The Correct Answer and Explanation is:
The correct answer is Option 2: Very acidic.
Explanation:
The pH scale measures the acidity or basicity of a solution, with a range from 0 to 14. A pH of 7 is considered neutral, with lower values indicating acidity and higher values indicating basicity (or alkalinity). The pH scale is logarithmic, meaning that each unit change on the scale represents a tenfold difference in the concentration of hydrogen ions (H⁺) in the solution.
- Acidic solutions have a pH less than 7, with the lower the pH, the stronger the acidity.
- Basic solutions (also called alkaline) have a pH greater than 7, with the higher the pH, the stronger the basicity.
- Neutral solutions have a pH of 7, like pure water.
A pH of 1.5 falls well below 7, which places the solution in the acidic range. To classify how acidic the solution is, consider the following:
- Very acidic solutions typically have pH values from 0 to 3. These solutions contain a high concentration of hydrogen ions (H⁺).
- Slightly acidic solutions would have pH values closer to 7 but still less than 7, typically between 5 and 6.
Since pH 1.5 is very far from neutral, with a high concentration of H⁺ ions, it is best described as very acidic. Common examples of substances with a very acidic pH include strong acids like hydrochloric acid (HCl), which has a pH close to 1, and sulfuric acid (H₂SO₄), which is also strongly acidic.
In contrast:
- Option 1: Slightly acidic would typically refer to pH values between 5 and 6, which is much higher than 1.5.
- Option 3 and Option 4: Slightly basic and very basic both describe pH values above 7, making them incorrect in this context.
Therefore, a solution with a pH of 1.5 is very acidic.