Which one of the following is commonly used as an indicator to measure the exact pH?

Question

Question

This question was previously asked in

RRB ALP CBT I 17 Aug 2018 Shift 3 Official Paper

Answer 1

The correct answer is Universal indicator.

Key Points

Acids are compounds that, when dissolved in water, form free hydrogen ions (H+ ions).
When bases are dissolved in water, they form hydroxyl ions (OH-).
Hydrogen ions are abundant in acidic solutions and limited in basic solutions.
The pH scale is used to determine the acidity or basicity of an acid or base.
The pH scale goes from 0 to 14 on the scale.
pH indicators are made up of several chemical compounds known as universal indicators.

Additional Information

Eosin:
- Eosin is the maximum appropriate stain to mix with an alum hematoxylin to illustrate the overall histological structure of a tissue.
Litmus:
- Litmus paper is filter paper that has been treated with soluble natural dyes provided by lichens.
- Litmus paper is a piece of paper that produces results that can be used as a pH indicator.
Phenolphthalein:
- Phenolphthalein is an organic compound that is used medicinally as a bleach.
- It has the chemical formula C20H14O4. It is written as “phph” or HIn. It is used in acid-base titration as an indicator.