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प्रश्न
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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उत्तर
A catalyst is a substance which changes the rate of a chemical reaction without undergoing a chemical change.
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संबंधित प्रश्न
MULTIPLE CHOICE QUESTIONS
Tick the most appropriate answer.
Which one of the following alters the rate of the chemical reaction without itself undergoing any change?
- temperature and Pressure
- concentration of reactants
- presence of catalyst
- none of these
TRUE \ FALSE
Positively charged electrode is called the anode. True or false ?
Fill in the blank
A new substance is formed in a _______ change.
Explain the following reaction with one suitable example of Decomposition reaction
Show with the help of diagram of electronic configuration how the following compound is formed from the constituent atoms.
Water
Give an example of a reaction where the following are involved
Pressure
Multiple choice:
Thermal decomposition of sodium carbonate will produce
State the original colour of the following substance and colour of residue obtained after heating.
Lead nitrate
Give a word equation for the following reaction.
Two solids which combine on heating, to give a liquid.
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.
Give balanced equation for the following conversion affected by heat alone on the substance:
Ammonium dichromate to nitrogen
Name the solid residual product formed reaction and state its colour during – thermal decomposition of the following substance.
Calcium hydroxide.
______ is not a chemical change.
What is the role of a catalyst in a chemical reaction?
Which of the following is not an “element + element → compound” type reaction?
Can a nickel spatula be used to stir copper sulphate solution? Justify your answer.
Assertion (A): Cutting paper into very small pieces is an irreversible change.
Reason (R): Physical changes are always reversible.
The reaction of H2 gas with oxygen gas to form water is an example of ______.
When milk is mixed with coffee decoction, the colour of milk and decoction changes due to ______.
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.
