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प्रश्न
Fill in the blanK
A .............is a substance which changes the rate of a chemical reaction without undergoing a chemical change.
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उत्तर
A catalyst is a substance which changes the rate of a chemical reaction without undergoing a chemical change.
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संबंधित प्रश्न
How do the following help in bringing about a chemical change?
heat.
Define catalyst.
Write the missing reactants and products and balance the equations.
\[\ce{KClO3 ->[heat]}\] ___________+ ____________
TRUE \ FALSE
A precipitation reaction takes place only in a solution.
TRUE \ FALSE
Ammonia is a good oxidizing agent.
State what you would observe when the following substance is heated in a glass test tube Copper (II) carbonate Red lead .
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 |
Give an example of a reaction where the following are involved
Heat
What do you observe? When
Barium chloride is added to sodium sulphate solution
Give an example of the following chemical changes.
A reaction where colour change is noticed.
State the original colour of the following substance and colour of residue obtained after heating.
Copper carbonate
State the original colour of the following substance and colour of residue obtained after heating.
Lead nitrate
Distinguish by heating the following in dry test tubs.
Ammonium Chloride and iodine.
State whether the following reaction is oxidation or reduction.
\[\ce{Na->Na+}\]
Name the solid residual product formed reaction and state its colour during – thermal decomposition of the following substance.
Zinc carbonate.
Name the solid residual product formed reaction and state its colour during – thermal decomposition of the following substance.
Calcium hydroxide.
What happens when cane sugar is strongly heated? Mention any two changes in it.
The changes in which new substance with new chemical properties are formed are ______.
Which of the following is/are true when milk changes into curd?
- Its state is changed from liquid to semi solid.
- It changes colour.
- It changes taste.
- The change cannot be reversed.
Choose the correct option from below:
Magnesium + oxygen → magnesium oxide.
2Mg + O2 → 2Mg O
