Natural Indicators

Q.

How do we test whether a substance is an acid or base? Explain the mechanism. Give examples of some substances that can be used for testing acids and bases.
[3 MARKS]

Q. China rose indicator in acidic solution changes its colour to ________________.

1. blue
2. yellow
3. dark pink
4. green

Q. Litmus is a natural indicator that is obtained from _____.

1. fungi
2. bacteria
3. lichen
4. parasite

Q. Which of the following can change the colour of red litmus to blue?

1. Vinegar
2. Lemon juice
3. Sodium hydroxide
4. Sulphuric acid

Q. Which of these is not a cereal?
(a) wheat
(b) rice
(c) turmeric
(d) corn

Q. Ammonia is ______ in nature since it turns red litmus blue.

1. highly acidic
2. slightly acidic
3. neutral
4. basic

Q. Ammonia is ______ in nature since it turns red litmus blue.

1. highly acidic
2. neutral
3. slightly acidic
4. basic

Q. A change in colour or smell of an indicator helps us to distinguish between an acid and a base.

1. True
2. False