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Question
Give an example of a reaction where the following are involved:
Close contact
Solution
\[\ce{Pb(NO3)2(s) + 2KI (s) -> 2KNO3 + PbI2 (s)}\]
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RELATED QUESTIONS
MULTIPLE CHOICE QUESTIONS
Tick the most appropriate answer.
Miscible liquids having slightly different boiling points can be separated by the
- evaporation
- distillation
- fractional distillation
- sedimentation
FILL IN THE BLANK
The new substances formed during a chemical reaction are called the ..................
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
The evolution of a gas during a chemical reaction is shown by an arrow pointing downwards. True or false ?
Write true or false :
When potassium iodide solution is added to lead acetate solution a red precipitate is formed.
Out of sodium and sulphur which is a metal? Explain its reaction with the oxygen.
Give an example of a reaction where the following are involved
Light
Define Photochemical reaction
Give an example
What do you observe? When
Water is added to the quick lime.
Select the correct answer for the following options:
The black residue obtained on heating copper carbonate.
Give a word equation for the following reaction.
An exothermic reaction where both the reactants are gases, one of which is oxygen.
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 water to quicklime.
State the following reaction represent oxidation or reduction.
\[\ce{Fe++->Fe+++}\]
Name the solid residual product formed reaction and state its colour during – thermal decomposition of the following substance.
Calcium hydroxide.
______ gas causes tears in our eyes while cutting onions.
The chemical change is ______.
Higher order Thinking question
A very hot glass on putting in cold water cracks. What does this change indicate?
Can a nickel spatula be used to stir copper sulphate solution? Justify your answer.
How can we prevent rusting?
Collect information about the types of fuels used for cooking in your area. Discuss with your teachers/parents/others which fuels are less polluting and why.
