Question

Tell me about the following indicators in detail:-

• Natural Indicator

• Synthetic Indicator

• Olfactory Indicator

• Phenolphthalein Indicator

Answer 1

Dear Friend,
Natural Indicator:-
A natural substance which can be used to determine the pH of another substance. For eg:-Red cabbage juice, grape juice, etc.
Synthetic Indicator:-
A synthetic indicator is a man-made chemical substances used to determine pH.
Olfactory Indicator:-
A substance whose smell varies depending on whether it is mixed to acidic or basic substance.
Phenolphthalein Indicator:-
A substance which turns colorless in acids and pink in basic solutions.

Answer 2

1) Natural Indicators -
These are the indicators that are obtained from natural substance.
Example - The most common example is of Litmus that is obtained from Lichen.It is a purple in color when it is neutral.It turns red in acidic solution while it turns blue in basic solutions.
Turmeric is also a natural indicator.

2) Synthetic Indicator -
Those indicators that are chemically prepared in laboratory for testing acids and bases are called synthetic indicators.
Example - Methyl Orange, Phenolphthalein

In acid solution, Methyl Orange changes to red while Phenolphthalein changes to colorless

In basic solution, Methyl Orange changes to yellow while Phenophthalein turns pink.

3)Olfactory Indicators -
 Those indicators that change their odor in acidic and basic solutions are called olfactory indicators.

Example -- Onions
Onions don't give their odor when in basic solutions, while in acidic solutions Onion give out their characteristic smell

Hope This Helps You!