Question

A solution which has pH 7 is :
A) Acid
B) Base
C) Neutral
D) None of these

Answer 1

Hint: The answer to this question is based on the general concept of chemistry that tells us about the pH scale that is used for acidity and basicity measurement and the fixed values for the acids and bases and also neutrality of the solutions.

Complete Solution :
In our lower classes, we have dealt with the very basic concept that measures acidity and basicity and also neutrality of the solutions.
- The measurement used is the pH scale which is defined as the negative logarithm of hydrogen ion molar concentration in the solution.
- pH is basically having fixed values for which the acidity is measured when the values are lower, that is acidic solutions have lower pH values whereas basic solutions are having the higher pH values.
- The pH scale has the standard values which have the value of 7 at room temperature that is at ${{25}^{0}}C$ and this value is considered to be the neutral value.
- pH is measured by using the instrument in laboratories which is called a pH meter.
Therefore, the value lower than this value indicates that the solution is acidic and the values greater than this indicate that the solution is basic.
So, the correct answer is “Option C”.

Note: Note that pH depends on the temperature. For instance, at the freezing point of water that is ${{0}^{0}}C$ the pH of pure water is about 7.47 and at the room temperature ${{25}^{0}}C$ it has the value pH = 7 and at boiling point that is at ${{100}^{0}}C$ it has the value pH = 6.14.