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प्रश्न
Write true or false :
Hydrogen sulphide has rotten egg smell .
विकल्प
True
False
उत्तर
True
APPEARS IN
संबंधित प्रश्न
Complete and balance the following chemical equations
Na + H2 O →
What do you observe when :
an iron nail is kept in tap water for few days
Balancing a chemical equation is based on
State what you would observe when the following substance is heated in a glass test tube Copper (II) carbonate Red lead .
Explain by writing a word equation.
Limestone powder disappears on adding to dilute hydrochloric acids.
What is a chemical reaction?
Give an example of a reaction where the following are involved
Catalyst
Define Photochemical reaction
Give an example
Write the chemical reaction where the following changes are observed.
Gas is evolved
Give reason for the following:
Molybdenum is used in the manufacture of ammonia.
Give reason for the following:
Colourless concentrated sulphuric acid in a test tube changes to blue on adding a small piece of copper to it.
Multiple choice:
Thermal decomposition of sodium carbonate will produce
Name: A brown gas
Write your observation and a balanced equation in the case of the following substances being heated.
Ammonium dichromate.
Complete the table given below.
| Heat on Zinc nitrate | Colour of residue |
Complete the table given below.
| Flame test for calcium chloride | Acid used for flame test |
Give a balanced equation for the conversion of an ammonium salt to a basic gas.
Photosynthesis is a chemical reaction that takes place in the presence of ______.
The changes in which new substance with new chemical properties are formed are ______.
Silver articles turning black: ______:: Boiling of H2O: physical change ______.
Arrange the following statements in correct sequence:
- One side is water-loving and other water-hating molecules.
- When you agitate the cloth, the dirt is surrounded by many molecules and taken away from the cloth.
- The dirt surrounded by the detergent molecules floats in the water making it dirty.
- Finally, the cloth is clean.
- The detergent molecules have two sides.
- Water hating goes and joins with dirt and oil in the cloth while the water-loving joins with the water molecules.
Which of the following is a chemical change?
Which of the following statement is incorrect for a chemical reaction?
State whether the following statements are true or false:
When a candle burns, both physical and chemical changes take place.
Classify the following processes into physical or chemical changes:
(i) Beating of aluminium metal to make aluminium foil.
(ii) Digestion of food.
(iii) Cutting of a log of wood into pieces.
(iv) Burning of crackers.
Give an example of a chemical reaction for each of the following situations:
A change in colour is observed.
The chemical name of baking soda is sodium bicarbonate.
Write the chemical reaction of baking soda with lemon.
