Question

What is meant by universal indicator?

Answer 1

Hint:This question gives us the knowledge about the indicators, acids and bases. Acids are the chemical species which can donate hydronium ions. Bases are the chemical species which can donate hydroxide ions.

Complete step by step answer:
-Universal indicators are defined as the substances which are the mixtures of various other indicators which provide diverse colors at different $pH$ values. It tells us about the acidic and basic nature of the substances.
-Whenever any acidic or a basic solution is added into the universal indicator, it leads to a new color which is used to determine the value of $pH$ of acidic or basic solutions by matching them with the colors of the $pH$ color chart.
-When a universal indicator is mixed with water, it generates a green color solution which indicates that the $pH$ of distilled water is $7$. Another example is lemon which turns $pH$ paper to vivid red from blue when it reacts with the universal indicators and shows the presence of hydronium ions.
-The universal indicator generally comprises water, phenolphthalein, $1$-Propanol, methyl red, sodium hydroxide, thymol blue monosodium salt and bromothymol blue monosodium.
-The main advantage of the universal indicator is that they represent a variety of colors within the $pH$ scale ranging between $1 - 14$. And the main disadvantages of universal indicators are that they cause skin inflammations, and can be absorbed through skin. They can also cause CNS depression, liver damage or kidney damage.

Note:
Always work with universal indicators very carefully as they are very harmful for our skin. And remember universal indicators are generally the mixtures of dyes which changes color over a $pH$ range $4 - 14$.