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प्रश्न
Explain the term ‘chemical reaction’ with special reference to – ‘reactants’ and ‘products’.
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उत्तर
A chemical reaction involves the breaking of existing bonds between atoms or groups of atoms of the reactants and leading to formation of new bonds forming new substances called the products.
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संबंधित प्रश्न
State whether the following statement is true or false. In case a statement is false, write the corrected statement.
Condensation of steam is not a chemical change.
Changes in which new substances are formed are called ______ changes.
When baking soda is mixed with lemon juice, bubbles are formed with the evolution of a gas. What type of change is it? Explain.
How would you show that setting of curd is a chemical change?
Fill in the blanK
A .............is a substance which changes the rate of a chemical reaction without undergoing a chemical change.
MULTIPLE CHOICE QUESTIONS
Tick the most appropriate answer.
Which one of the following alters the rate of the chemical reaction without itself undergoing any change?
- temperature and Pressure
- concentration of reactants
- presence of catalyst
- none of these
FILL IN THE BLANK
On reaction with sulphuric acid solution, barium chloride forms a white precipitate of ........ sulphate.
How is a strong electrolyte different from a weak electrolyte?
Fill in the blank:
During a chemical reaction transfer of ________ takes place.
Write true or false :
Hydrogen sulphide has rotten egg smell .
Explain the following reaction with one suitable example of Double decomposition reaction.
Give an example of a reaction where the following are involved
Electricity
Give reason for the following:
Silver nitrate solution is kept in coloured bottles.
Name: Two carbonates do not produce carbon dioxide on heating.
Complete the table given below.
| Addition of dil. H2SO4 to KHCO3 | Name of residue obtained |
Complete the table given below.
| Addition of dil. H2SO4 to zinc | Test for gas evolved |
Silver articles turning black: ______:: Boiling of H2O: physical change ______.
Match the following:
| 1. | Sodium Chloride | a. | CaSO41/2H2O |
| 2. | Calcium sulphate dihydrate | b. | C2H5Oh |
| 3. | Magnesium sulphate hydrate | c. | CaSO4.2H2O |
| 4. | Calcium sulphate hemihydrate | d. | NaCl |
| 5. | Phenol | e. | MgSO4.H2O |
Classify the following as physical or chemical properties
Most metal oxides form alkalis on interacting with water.
A student took a solution of copper sulphate in a beaker and put a clean iron nail into it and left it for about an hour.
What changes do you expect?
