Question

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

Answer 1

Universal indicator is a pH indicator to indicate the acidity and alkalinity of the solutions. The universal indicator turns red for strong acids and turns blue for strong base solutions. Hence it will provide the idea to use it as a pH indicator.

Complete step by step answer:
A..Acids: Acids are those species which turn blue litmus to red litmus and have a pH range as: $1 - 7$. For example: acetic acid.
B.Bases: Bases are those species which turn red litmus to blue litmus and have a pH range as: $7 - 14$. For example: sodium hydroxide.
C.Neutral: Those species which neither turn blue litmus to red litmus nor turn red litmus to blue litmus and have pH equal to $7$, are known as neutral species. For example: water.
There are also many other indicators which can distinguish between acids and bases. Some of them are: Litmus paper, methyl orange, universal indicator, etc.
Litmus paper: It is an acid-base indicator. If a compound turns blue litmus to red then it will be an acid and if the compound turns red litmus to blue litmus then the compound will be basic in nature.
Methyl orange: It is an indicator which can tell us who is acid and who is base. For example: if neutral water or alkaline (basic) water is poured on methyl orange indicator then it turns to yellow and if acid water is poured on it then the colour of methyl orange changes to red.
Universal indicator: It is like a litmus paper indicator. It turns red if the solution is acidic in nature and turns blue if the solution is basic or alkaline in nature.
In the question, it is given that the solution turns the universal indicator to red. It means the solution will be strongly acidic in nature.

So, the correct answer is Option B .

Note:
Neutral water has pH equal to seven and if the water is acidic in nature then its pH is about $4.2$. Acidic water is harmful to drink. So we should avoid use of acidic water. Carbon dioxide is the main reason for the acidity of water