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प्रश्न
Circle the odd one out. Give reason for your choice
पर्याय
Growth of a child
Blinking of eye
Rusting
Germination of a seed
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उत्तर
Rusting
Reason: Rusting is undesirable change. Others three are desirable changes.
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संबंधित प्रश्न
How do the following help in bringing about a chemical change?
catalyst .
Complete and balance the following chemical equation:
\[\ce{Pb(NO3)2 ->[Heat]}\]
Write the missing reactants and products and balance the equations.
................+ HCI `→` NaCI + `"H"_2"O"` + .........................
Out of sodium and sulphur which is a metal? Explain its reaction with the oxygen.
Choose the correct option from the bracket and explain the statement giving reason.
(Oxidation, displacement, electrolysis, reduction, zinc, copper, double displacement, decomposition)
The conversion of ferrous sulphate to ferric sulphate is ______ reaction.
Give reason for the following:
Blue solution of copper sulphate changes to green when a piece of iron is added to this solution.
Give an example of the following chemical changes.
A reaction where colour change is noticed.
Name: Gas with rotten egg smell.
What is observed in performing the following :
| Hydrogen | Oxygen | Carbon dioxide | Chlorine | |
| Litmus test | ||||
| Apply a burning splint to the gas | ||||
| Colour of gas | colourless | colourless | colourless | greenish-yellow |
| Odour of gas |
Give a chemical test to distinguish between the following gases.
H2 and O2
Write your observation and a balanced equation in the case of the following substances being heated.
Copper nitrate.
Explain the term ‘chemical reaction’ with special reference to – ‘reactants’ and ‘products’.
State the following reaction represent oxidation or reduction.
\[\ce{Cu++->Cu}\]
______ gas causes tears in our eyes while cutting onions.
Analogy:
H2O: Water:: NaCl: ______.
Classify each of the following, as a physical or a chemical change. Give reasons.
(a) Drying of a shirt in the sun.
(b) Rising of hot air over a radiator.
(c) Burning of kerosene in a lantern.
(d) Change the colour of black tea by adding lemon juice to it.
(e) Churning of milk cream to get butter.
Give two examples for the following case:
Chemical changes
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?
When magnesium is burnt in the air, a new substance is formed which is ______.
______ is the chemical name of limestone.
