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प्रश्न
Explain the following reaction with one suitable example of Decomposition reaction
उत्तर
Decomposition reaction : In this reaction a substance breaks up on heating to form two or more simpler substances, e.g. Electrolysis of water.
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संबंधित प्रश्न
Changes in which new substances are formed are called ______ changes.
How do the following help in bringing about a chemical change?
heat.
MULTIPLE CHOICE QUESTIONS
Tick the most appropriate answer.
Reduction is a chemical reaction in which there is
- removal of hydrogen
- removal of oxygen
- addition of oxygen
- none of these
TRUE \ FALSE
Copper can displace iron from iron sulphate.
TRUE \ FALSE
Ammonia is a good oxidizing agent.
TRUE \ FALSE
Evaporation of water is a physical change. True or false ?
TRUE \ FALSE
The evolution of a gas during a chemical reaction is shown by an arrow pointing downwards. True or false ?
Copper carbonate when heated, it turns :
What is the reaction called when oxidation and reduction take place simultaneously? Explain with one example.
Match the pairs.
| a. | Photosynthesis | i. | Tendency to lose electrons |
| b. | Water | ii. | Reactant in combustion process |
| c. | Sodium chloride | iii. | Chemical change |
| d. | Dissolution of salt in water | iv. | Covalent bond |
| e. | Carbon | v. | Ionic bond |
| f. | Fluorine | vi. | Physical change |
| g. | Magnesium | vii. | Tendency to form anion |
Write the chemical reaction where the following changes are observed.
Precipitate is formed
Multiple choice:
Thermal decomposition of sodium carbonate will produce
Name: Gas with rotten egg smell.
What do you observe when Cl2 is passed through potassium iodide (KI) solution.
Give a chemical test to distinguish between the following gases.
H2 and O2
Represent the addition of dilute sulphuric acid to zinc by means of a chemical equation. State the function of the arrow between the reactants and products.
Select the correct answer for the following options:
The basic gas obtained when two gases react in presence of a catalyst and the reaction is exothermic.
Give a word equation for the following reaction.
A salt which reacts with ammonium hydroxide to give a reddish brown precipitate.
What is a chemical reaction?
Complete the table given below.
| Addition of dil. H2SO4 to zinc | Test for gas evolved |
Select the correct answer from the options given below:
State the gaseous product formed, when
An ammonium salt reacts with an alkali.
Name the solid residual product formed reaction and state its colour during – thermal decomposition of the following substance.
Lead nitrate.
What is the use of indicator?
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.
Iron benches kept in lawns and gardens get____________. It is a _________ change because a new _________ is formed.
Rusting of iron is ______.
______ occurs in the absence of air and in the presence of micro-organisms such as yeast.
Write a note on the following:
Fermentation
Write the characteristics of chemical change.
Photosynthesis is a chemical charge. Justify your answer.
