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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
Fill in the blanK
A .............is a substance which changes the rate of a chemical reaction without undergoing a chemical change.
FILL IN THE BLANK
The new substances formed during a chemical reaction are called the ..................
TRUE \ FALSE
Ammonia is a good oxidizing agent.
Fill in the blank:
The basic conditions necessary for a chemical reaction is _______
State the conditions necessary for a chemical change or reaction.
Give an example of the following chemical change.
A reaction where colour change is noticed
Complete and balance the following reaction:
\[\ce{NH3 + O2 ->[\Delta]}\]
State the original colour of the following substance and colour of residue obtained after heating.
Copper carbonate
What do you observe when dilute sulphuric acid is added to the following:
Sodium Sulphide
Write your observation and a balanced equation in the case of the following substances being heated.
Copper nitrate.
Select the correct answer for the following options:
The basic gas obtained when two gases react in presence of a catalyst and the reaction is exothermic.
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 – Thermal decomposition of mercury [II] oxide.
Complete the table given below.
| Heat on ammonium dichromate | Name of neutral gas evolved |
Complete the table given below.
| Addition of dil. H2SO4 to FeS | Odour of gas evolved |
Complete the table given below.
| Heat on sodium chloride | Colour imparted to flame during flame test |
Give a balanced equation for the conversion of an ammonium salt to a basic gas.
Name the solid residual product formed reaction and state its colour during – thermal decomposition of the following substance.
Calcium hydroxide.
A student took a solution of copper sulphate in a beaker and put a clean iron nail into it and left it for about an hour.
Are these changes chemical in nature?
Give an example where heat, light, and sound are produced during a chemical change.
What are the chemical reactions that occur in everyday life?
