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Question
Fill in the blanK
A .............is a substance which changes the rate of a chemical reaction without undergoing a chemical change.
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Solution
A catalyst is a substance which changes the rate of a chemical reaction without undergoing a chemical change.
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RELATED QUESTIONS
Fill in the blank
A catalyst either ................or ............... the rate of a chemical change but itself remains ............... at the end of the reaction.
Give a 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
Temperature at which a liquid starts boiling is known as the boiling point of that liquid. True or false ?
Fill in the blank
A change in which the substance can be brought back to its original state is called a _______ change.
Define chemical reaction.
Fill in the blank:
The basic conditions necessary for a chemical reaction is _______
Write true or false :
Hydrogen sulphide has rotten egg smell .
Write true or false :
When potassium iodide solution is added to lead acetate solution a red precipitate is formed.
What is a chemical reaction?
Define the following term:
Precipitate
State the type of reactions for the following represent and balance the ones that are not balanced.
NaOH + HCl → NaCl + H2O
Give an example of the following chemical changes.
A reaction involving
(i) Change of state
(ii) formation of precipitate
Give one example electrochemical reaction.
Name: A greenish-yellow gas.
Explain the term ‘chemical reaction’ with special reference to – ‘reactants’ and ‘products’.
Represent the addition of dilute sulphuric acid to zinc by means of a chemical equation. State the function of the arrow between the reactants and products.
Give reason for the following:
Even though rusting is an exothermic reaction, the heat evolved when an iron nail rusts is unnoticeable.
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.
Which of the following is a chemical change?
