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प्रश्न
If you leave a piece of iron in the open for a few days, it acquires a film of brownish substance, called rust.
Do you think formation of rust from iron is a chemical change?
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उत्तर
Yes, rusting is a chemical change since a new substance is formed.
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संबंधित प्रश्न
Give reason.
Acidic soil is treated with quick lime.
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 |
Fill in the blank.
Melting of ice is a _______ change.
What do you observe? When
Water is added to the quick lime.
What do you observe? When
Sodium chloride solution is added to silver nitrate solution.
Give a word equation for the following reaction.
A compound which on heating shows – colour change from brown to yellow.
Name the following:
The type of change physical or chemical involved – ‘during respiration in human beings’.
Explain the Silver nitrate solution is kept in coloured reagent bottles in the laboratory.
What happens when cane sugar is strongly heated? Mention any two changes in it.
State whether the following statement is true or false:
When a candle burns, both physical and chemical changes take place.
