Question

The solutions which do not change the colour of either red or blue litmus are known as:
A.Neutral solution
B.Alkaline solution
C.Brine solution
D.Acidic solution

Answer 1

We know that litmus papers are used to identify whether a solution is acidic , basic or neutral in nature. Litmus papers are water soluble , They are made from lichens. Litmus papers are used as indicators.

Complete step by step solution:
We know that whenever we add an acidic solution in a blue litmus paper , the colour of the paper changes to red colour. Whenever we add basic solution in a red litmus paper the colour of the paper changes to blue colour. And when a particular solution does not change the colour of either red or blue litmus paper it is known to be a neutral solution. It is neither acid nor basic in nature .The $pH$ value of neutral solutions is always $7$ in room temperature. Litmus papers are made up of lichens.
So from the above explanation and discussion it is clear to us that

The correct answer of the given question is option: A. Neutral solution

Additional information:
The concept of $pH$ is used to understand the basicity and acidity of a solution. The $pH$ of a solution is given by the formula $pH = - \log [{H^ + }]$ . $[{H^ + }]$ is the concentration of the hydrogen ion of the solution. The $pH$value of an acidic solution is always less than $7$. The $pH$ of a basic solution is always in between $7 - 14$. Neutral solutions have $pH$of $7$ .

Note:
Always remember that the neutral solution does not change the colour of either red or blue litmus paper. Neutral solutions have $pH$ of $7$. Basic solution changes red litmus into blue and acidic solution changes blue litmus to red.