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Home » Class 10 » Acid Bases and Salts » Indicators

Indicators

Last Updated on September 18, 2022 By Mrs Shilpi Nagpal

Question 1 What is an indicator?

Question 2 Name the common indicators used to test acid, bases and salts?

Question 3 What are olfactory indicators. Give examples?

Question 4 What is the colour of Phenolphthalein in acidic and basic medium?

Question 5 What is the colour of methyl orange in acidic and basic medium?

Acid, Bases and Salts

On the basis of chemical properties, all the compounds can be classified into three groups:

1)Acids

2)Bases

3)Salts

Indicator

An indicator is a dye that changes colour when it is put into an acid or a base.

An indicator tells us whether a given substance is an acid or a base by change in its colour.

The three common indicators to test for acids and bases are

1)Litmus

2)Methyl Orange

3)Phenolphthalein

Indicator Acid Neutral Basic
Red Litmus Red Red Blue
Blue Litmus Red Blue Blue
Phenolphthalein Colourless Colourless Pink
Methyl Orange Red Orange Yellow

1)Orange juice turns blue litmus to red,so orange juice is acidic in nature.

2)Sodium Hydroxide turns red litmus to blue,so it is basic in nature.

Litmus is a natural indicator whereas Methyl orange and phenolphthalein are synthetic indicators.

Olfactory Indicators

Those substances whose smell or odour changes in acidic or basic solution are called olfactory indicators.

For Ex:Onion and Vanilla extract

Filed Under: Acid Bases and Salts, Class 10 Tagged With: blue litmus, indicator, methyl orange, olfactory indicators, phenolphthalein, red litmus

About Mrs Shilpi Nagpal

Author of this website, Mrs. Shilpi Nagpal is MSc (Hons, Chemistry) and BSc (Hons, Chemistry) from Delhi University, B.Ed. (I. P. University) and has many years of experience in teaching. She has started this educational website with the mindset of spreading free education to everyone.

Reader Interactions

Comments

  1. Manju Bala says

    July 5, 2020 at 10:08 am

    That’s good

  2. swetha says

    September 21, 2020 at 6:40 pm

    very good website. nice explanation and easy to grasp!
    well done team 🙂

  3. Megha says

    June 7, 2021 at 10:05 pm

    That’s great mam …. Well done

  4. Joy says

    June 27, 2021 at 10:29 pm

    Very Good mam it is Very Educating Keep it up

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