Question

Name two synthetic indicators.

Answer 1

Hint: Synthetic Indicator - An indicator prepared from artificial substances is known as a synthetic indicator. In simple words, all the indicators which are not natural are known as man-made or synthetic indicators.

Complete step-by-step answer:
> The two synthetic indicators are phenolphthalein and methyl orange.
1) Phenolphthalein is an indicator used to determine the pH of the various solutions. Its solution is prepared by dissolving it in alcohol. Its solution is colorless. When a few drops of phenolphthalein are added to a basic solution it changes into a deep pink color. It remains colorless in acidic and neutral solutions.
> Phenolphthalein is used as an indicator of pH change when the pH is between ${ 8.2 }$ and ${ 10 }$ (basic solutions).

2) Methyl orange is a pH indicator frequently used in titrations.
It is often used in titrations because of its clear and distinct color change. Since it changes color at the pH of a mid-strength acid, it is normally utilized in titrations for acids. Unlike a universal indicator, methyl orange does not have a full spectrum of color change but has a sharper endpoint.
> Methyl orange is used as an indicator of pH change when the pH is between ${ 3.1 }$ and ${ 4.4 }$ (acidic solutions).

Note: The possibility to make a mistake is that in the pH range where both the indicators change the colors. In phenolphthalein, it is colorless but becomes pink above 8.2 pH and the color change interval of methyl orange is 3.1 to 4.5 pH range.