The pH scale is a fundamental concept in chemistry used to measure how acidic or basic (alkaline) a water-based solution is. This scale typically ranges from 0 to 14.
A solution is considered acidic when its pH value is below 7. This indicates that the concentration of hydrogen ions (\(H^+\)) in the solution is greater than the concentration of hydroxide ions (\(OH^-\)). The lower the pH value, the stronger the acidity of the solution.
On the other hand, a solution is defined as neutral if its pH value is exactly 7. In a neutral solution, the concentration of hydrogen ions (\(H^+\)) is equal to the concentration of hydroxide ions (\(OH^-\)). Pure water is an example of a neutral solution.
A solution is classified as basic or alkaline when its pH value is greater than 7. In basic solutions, the concentration of hydroxide ions (\(OH^-\)) exceeds the concentration of hydrogen ions (\(H^+\)).
The relationship between pH value and the nature of the solution can be summarized as follows:
| pH Range | Solution Type |
|---|---|
| pH < 7 | Acidic |
| pH = 7 | Neutral |
| pH > 7 | Basic (Alkaline) |
Given that the question asks to identify the type of solution when the pH value is less than 7, we refer to the definition above. A pH value strictly less than 7 signifies an acidic condition. Common examples of acidic substances include vinegar, lemon juice, and stomach acid.
Let's look at why the other options provided are not the correct classification for a solution with a pH less than 7:
Therefore, a solution with a pH value less than 7 is definitively an acidic solution.
Number of electrons present in the species H2, He, H2 and O2 respectively are:
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Which of the following is formed when carbon dioxide reacts with calcium hydroxide?
Which of the following types of reaction represents formation of slaked lime from calcium oxide and water?
Which of the following has a pH value of 7?