MEDIUM
7th CBSE
IMPORTANT
Earn 100

Make a natural indicator from China rose petals. 

Materials: China rose petal, boiling water

Let's do: 1. Take some petals of China rose (Gudhal) in a beaker and add boiling water to this.
2. Keep the mixture undisturbed for some time till the water becomes coloured. This coloured water can
now be used as an indicator.
3. Put different solutions with China rose extract indicator. Record your observations.

Observations:

S.No Solution Effect on China rose extract Inference
1 Milk     
2 Lemon juice    
3 Soap solution    
4 Tomato juice    
5 Tamarind juice    

Important Questions on Acids, Bases and Salts

HARD
7th CBSE
IMPORTANT
Find out the pH of, H2SO4, HCl, and HNO3 and compare their acidic strength.
MEDIUM
7th CBSE
IMPORTANT
Find out some other examples of hydrated salts. Also indicate the water of crystallisation in them.
MEDIUM
7th CBSE
IMPORTANT
Which of the following is not an organic acid?
MEDIUM
7th CBSE
IMPORTANT
Which of the following indicators turns green when treated with a basic solution?
EASY
7th CBSE
IMPORTANT
Which of the following salts is used in the baking of cakes?
MEDIUM
7th CBSE
IMPORTANT
Which of the following acids is present in apples?
MEDIUM
7th CBSE
IMPORTANT
Which of the following bases is used to neutralise the acidic soil?
MEDIUM
7th CBSE
IMPORTANT
Which of the following bases is used to treat acidity?