Question

A universal indicator turns red in a solution. Hence, the pH of the solution is:
A.Neutral
B.Strong acid
C.Weak acid
D.Slightly alkaline

Answer 1

The universal indicator color shows that the universal indicator turns red when it is added to a strong acid it turns into purple and when it is added into a strong base it turns into yellowish-green. The range of acid and base defined by the pH scale. The color change of this indicator is caused by the dissociation of the hydrogen ion.

Complete step by step answer:
The universal indicators are known as pH indicators. pH indicators turn the color of solution by the dissociation of hydrogen ion. There are several smooth color changes over a pH value range from 1 to 14 to indicate the acidity or alkalinity of solutions.
In the strong acidic media, the Universal indicator turns red in a solution and in the basic media it turns purple also.
So, as we know about the pH scale, the range of pH in acidic media is 0 to 7.
Hence, strong acid contains 0 to 7 value of pH that’s why the universal indicator turns red in solution.

Therefore, option(B) is the correct answer.

Additional information:
Indicators are used for the color change of the presence or absence of a concentration of chemical species such as an acid and a base in a solution. There are different types of indicators which work to turn color in solutions.

Note:
Universal indicators supplied as a solution or as universal indicator papers. It is a mixture of several different indicators. This is measured by using pH scale, which runs from pH 0 to 14. Neutral solutions are pH 7 exactly. Acidic solutions have pH value less than 7 and alkali have greater than 7.