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प्रश्न
Explain the following reaction with one suitable example of Decomposition reaction
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उत्तर
Decomposition reaction : In this reaction a substance breaks up on heating to form two or more simpler substances, e.g. Electrolysis of water.
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संबंधित प्रश्न
State whether the following statement is true or false. In case a statement is false, write the corrected statement.
Condensation of steam is not a chemical change.
What are chemical reactions?
What do you observe when :
an iron nail is kept in tap water for few days
Fill in the blank
A change in which the substance can be brought back to its original state is called a _______ change.
A chemical equation is a statement that describes a chemical change in terms of
State the original colour of the following substance and colour of residue obtained after heating.
Zinc carbonate
Give a chemical test to distinguish between the following gases.
H2 and CO2
Give a chemical test to distinguish between the following gases.
HCl and H2S
Give a chemical test to distinguish between the following gases.
HCl and Cl2
Distinguish by dilute sulphuric acid.
Sodium Sulphite and sodium carbonate?
Give a word equation for the following reaction.
Two solids which combine on heating, to give a liquid.
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 acid to an active metal.
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.
Complete the table given below.
| Addition of dil. H2SO4 to KHCO3 | Name of residue obtained |
Complete the table given below.
| Flame test for calcium chloride | Acid used for flame test |
State the following reaction represent oxidation or reduction.
\[\ce{Cu++->Cu}\]
Higher order Thinking question
Peeled and unpeeled banana does not look the same. Does that mean peeling banana is a chemical change?
State whether the following statement is true or false:
When a candle burns, both physical and chemical changes take place.
What is thermochemical reactions?
