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प्रश्न
Define; catalyst.
उत्तर
Catalyst: A catalyst is a substance that either increases or decreases the rate of a chemical reaction without itself undergoing any chemical change during the reaction.
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संबंधित प्रश्न
When carbon dioxide is passed through lime water, it turns milky due to the formation of ______.
Changes in which new substances are formed are called ______ changes.
Complete and balance the following chemical equations:
N2 + O2 →
Complete and balance the following chemical equations
Na + H2 O →
Give reason.
Wasp sting is treated with vinegar.
MATCH THE COLUMNS
| 1 . `H_2` + `CI_2` `→` 2HCI | a. displacement reaction |
| 2. `2FeCI_3`+ `H_2` `→` `2FeCI_2` +2HCI` | b. addition of an electronegative redical |
| 3. Fe + `CuSO_4` `→``FeSO_4` +Cu` | c. removal of an electronegative redical |
| 4. `2H_2O` +`4NO_2`+`O_2` `→` `4HNO_3` | d.reduction by adding hydrogen |
| 5. 3Fe +`3CI_2` `→` `2FeCI_3` | e.electrolysis of water |
| 6. `FeCI_3`+ 3NaOH `→``Fe(OH)_3``↓`+NaCI | F.double decomposition,precipitation reaction |
| 7.`2H_2O` `→` `2H_2``↑`+`O_2` | e. combination or synthesis reaction |
TRUE \ FALSE
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Show with the help of diagram of electronic configuration how the following compound is formed from the constituent atoms.
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Give an example
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A reaction of a type: AB + CD → AD + CD, involves
Give an example of the following chemical changes.
A reaction involving
(i) Change of state
(ii) formation of precipitate
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Give a chemical test to distinguish between the following gases.
CO2 and SO2
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What is a chemical reaction?
Complete the table given below.
| Heat on iodine crystals | Colour of vapours evolved |
______ change results in the change of the substance.
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 the taste.
- The change cannot be reversed.
Choose the correct option from below:
Give two examples for each of the following cases:
Chemical changes.
Is the conversion of milk into ice cream a chemical change?
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Reason (R): Physical changes are always reversible.
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