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प्रश्न
Give a word equation for the following reaction.
A compound which on heating shows – colour change from brown to yellow.
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उत्तर
Lead dioxide →Lead oxide + Oxygen
2Pb02 → 2PbO + 02 (l)
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संबंधित प्रश्न
Give reason .
A person suffering from acidity is advised to take an antacid.
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
FILL IN THE BLANK
Distillation is a method of obtaining pure ............. from a solution.
Write true or false :
No new substance is formed during a chemical reaction.
Name the type of chemical reaction shown by the following equation:
CaCO3 → CaO + CO2
A solution of a substance ‘X’ is used for white washing write the reaction of the substance ‘X’ named in (a) above with water.
Give an example of the following chemical change.
Two gases combine to form white solid
Give reason for the following:
Colourless concentrated sulphuric acid in a test tube changes to blue on adding a small piece of copper to it.
State the type of reactions for the following represent and balance the ones that are not balanced.
Cl2 + 2KBr → 2KCl + Br2
Complete and balance the following reaction:
\[\ce{Pb(NO3)2 ->[\Delta]}\]
Complete the following table and write your observations.
|
Hydrogen sulphide |
Ammonia |
Sulphur dioxide |
Hydrogen chloride |
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Shake the gas with red litmus solution |
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Shake the gas with blue litmus solution |
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Apply a burning splint to a gas |
Complete the table given below.
| Heat on ammonium dichromate | Name of neutral gas evolved |
State the following reaction represent oxidation or reduction.
\[\ce{Al->Al+++}\]
______ is not a chemical change.
What is the role of a catalyst in a chemical reaction?
Discuss how acid rain occurs due to emission of smoke from vehicles and industries?
Which of the following is/are true when milk changes into curd?
- Its state is changed from liquid to semi solid.
- It changes colour.
- It changes taste.
- The change cannot be reversed.
Choose the correct option from below:
Write a note on the catalyst.
Both CO2 and H2 gases are ______.
______ is the chemical name of rust.
