Question

What colour does universal indicator go in a liquid with a pH of 9?

Answer 1

Hint: A universal indicator or the pH indicator gives us information about the acidity or basicity of the compounds and exhibits several colours to different values of the pH. It would be green colour if the pH is 7, red colour to the acidic pH and violet colour to the basic pH.

Complete step by step solution:
-First, we should know what pH is, it gives us the measure of acid/base strength of any solution. pH scale ranges from 0-14, 7 is neutral, below 7 it represents acidic and above 7 it represents basic.
-By the universal indicator, we simply mean a mixture of different colours of dyes and it tells us about the pH of any substance as its colour changes depending on the pH of that very substance and tells us if the substance is acidic, basic or neutral. So, therefore, it is also called as the pH indicator.
-The universal indicator has different colours to represent whether the compound is acidic, basic or neutral i.e. it indicates yellow to red colour for strongly acidic solutions, blue to dark purple colour for the strongly basic solutions and green colour for the neutral solutions.
-Since, the pH 9 falls under the category of the base being having pH value more than 7, the colour indicated by the universal indicator when dipped in the liquid would be close to the purple and will give blue colour since it is a weak base, not a strong base.

Hence, the universal indicator when going in a liquid with a pH of 9 will give blue colour indicating that it is a weak base.

Note: The universal indicators or the indicator paper are basically used in the labs for the purpose to identify whether the given compound or the substance is an acid or the alkali (base).