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प्रश्न
Differentiate between the following:
A catalyst and a promoter.
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उत्तर
- Catalyst: “A substance that alters the rate of a chemical reaction.”
e.g. MnO2, V2O5, Fe, Pt. etc.
The positive catalyst: A catalyst that speeds up the reaction.
Negative catalyst: A catalyst that reduces the rate of reaction, e.g. alcohol.
Enzymes are biological catalysts present in the human body and accelerate the biochemical reactions in the body. - Promotors: Promotors are a catalyst to catalyst, i.e. a substance which increases the activity of a catalyst.
Molybdenum [MO] is added to the catalyst iron [Fe] to increase its efficiency.
APPEARS IN
संबंधित प्रश्न
What do you observe when ammonium chloride is dissolved in water.
MULTIPLE CHOICE QUESTIONS
Tick the most appropriate answer.
Heat energy is evolved in these reactions
- Thermal decomposition reactions
- Exothermic reactions
- Endothermic reactions
- None of these
Identify the endothermic and exothermic reaction.
HCl + NaOH → NaCl + H2O + heat
State which type of chemical reaction proceeds with evolution of heat energy.
Give an example with a balanced equation, of the following reaction:
exothermic reaction
Give an example with a balanced equation, of the following reaction:
endothermic reaction
Match the following:
| Colum I | Column II | ||
| 1. | Alloying | a. | Exothermic change |
| 2. | Crystallization | b. | Periodic change |
| 3. | Soap powder + water | c. | Mixing of molten solids |
| 4. | Seasonal changes | d. | Pure solid |
Give examples of the endothermic process.
Complete the following table:
| Chemical Reactions | Name reaction type |
| \[\ce{C(s) + O2(g) -> CO2(g)}\] | (a) ________ |
| \[\ce{Zn(s) + CuSO4(aq) ->}\] (b) _________ | Displacement reaction |
| \[\ce{2Cu(s) + O2(g) ->[heat] 2CuO(s)}\] | (c) _________ |
| \[\ce{C(s) + 2H2(g) -> CH4(g)}\] | (d) _________ |
| \[\ce{CaO(s) + H2O(l) -> Ca(OH)2(aq) + heat}\] | (e) _________ |
| \[\ce{CaCO3(s) + Heat ->}\] (f) _________ | Endothermic Reaction |
Give scientific reasons.
While preparing dilute sulphuric acid from concentrated sulphuric acid in the laboratory, the concentrated sulphuric acid is added slowly to water with constant stirring.
