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प्रश्न
A chemical reaction is often accompanied by external indications or characteristics which include –
- Colour change
- Effervescence or gas evolved
- Evolution or absorption of heat
- Formation of a precipitate.
With reference to each of the above indications, state the external indication seen during – Addition of dilute hydrochloric acid to silver nitrate.
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उत्तर
Addition of dil. hydrochloric acid to silver nitrate: A white coloured precipitate of AgCl is seen.
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संबंधित प्रश्न
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 |
What are the characteristics of a chemical reaction ? A chemical reaction is characterised by an irreversible change in which a new substance is formed.
Write balanced chemical equations for the reactions represented by word equations in the conditions for chemical reaction.
Name the type of chemical reaction shown by the following equation:
NaOH + HCl → NaCl + H2O
Give an example of a reaction where the following are involved:
Solution
What do you understand by precipitation reaction? Explain with examples.
Complete and balance the following reaction:
NaCl(aq) + AgNO3(aq) →
Complete and balance the following reaction:
\[\ce{NH3 + O2 ->[\Delta]}\]
Distinguish by heating the following in dry test tubs.
Zinc carbonate, Copper carbonate and lead carbonate.
Write your observation and a balanced equation in the case of the following substances being heated.
Copper nitrate.
Write your observation and a balanced equation in the case of the following substances being heated.
Zinc carbonate.
Give a word equation for the following reaction.
A compound which on heating shows – colour change from brown to yellow.
What is a chemical reaction?
A chemical reaction is often accompanied by external indications or characteristics which include –
- Colour change
- Effervescence or gas evolved
- Evolution or absorption of heat
- Formation of a precipitate.
With reference to each of the above indications, state the external indication seen during – Thermal decomposition of mercury [II] oxide.
Give a suitable example with an equation to show the representation of a chemical reaction.
Name the solid residual product formed reaction and state its colour during – thermal decomposition of the following substance.
Calcium hydroxide.
The water we drink is a combination of hydrogen and oxygen.
The simplest method of preventing rusting of iron is to coat it with oil, grease, or paint. The reason being ______.
Give an example where heat, light, and sound are produced during a chemical change.
