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प्रश्न
What is an indicator? Name three common indicators.
What is an indicator?
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उत्तर १
Indicators are substances that show a distinct change (colour or odour) simultaneous to a change in concentration of ions such as H+ and OH- ions.
Examples: Methyl orange, phenolphthalein and litmus solution.
उत्तर २
An indicator or acid-base indicator is a chemical substance which indicates the acidic or basic nature of a solution by suitable colour change.
संबंधित प्रश्न
A milkman adds a very small amount of baking soda to fresh milk. Why does he shift the pH of the fresh milk from 6 to slightly alkaline?
The property which is not shown by acids is:
(a) they have sour taste
(b) they feel soapy
(c) they turn litmus red
(d) their pH is less than seven
(b) Name the acid or alkalis used to make (i) car batteries (ii) explosives (iii) soaps (iv) fertilisers.
The pH values of three acids A, B and C having equal molar concentrations are 5.0, 2.8 and 3.5 respectively. Arrange these acids in order of the increasing acid strengths.
The pH values of five solutions A, B, C, D and E are given below:
| A | 1 |
| B | 5 |
| C | 7 |
| D | 11 |
| E | 13 |
Solution A turns universal indicator blue to purple whereas solution B turns universal indicator orange to red
What will be action of solution B on litmus?
Solution A turns universal indicator blue to purple whereas solution B turns universal indicator orange to red.
Name any two substances which can give solutions like A.
Solution A turns universal indicator blue to purple whereas solution B turns universal indicator orange to red.
Name any two substances which can give solutions like B.
Name any two synthetic acid-base indicators.
Using the knowledge of acids and bases, write a secret message with the help of baking soda and beet root. Explain how it works.
(Hint: Prepare baking soda solution in water. Use this solution to write the message on a sheet of white paper with a cotton bud. Rub a slice of fresh beetroot over the message.)
