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प्रश्न
Define chemical reaction.
उत्तर
Chemical reaction : Any chemical change in matter which involves its transformation into one or more new substances is called a chemical reaction.
संबंधित प्रश्न
What are (i) positive catalysts and (ii) negative catalysts? Support your answer with one example for each of them.
Complete and balance the following chemical equations:
`"H"_2"S"` + `"CI"_2` `→`
What do you observe when Iron nail is kept in copper sulphate solution for sometime.
TRUE \ FALSE
Weak electrolytes dissociate partially in their aqueous or fused state.
Fill in the blank
A change in which the substance can be brought back to its original state is called a _______ change.
State four conditions necessary for chemical reactions to take place.
Write true or false :
No new substance is formed during a chemical reaction.
Write true or false.
A chemical equation gives only qualitative information of a chemical reaction.
Name the type of chemical reaction shown by the following equation:
NaOH + HCl → NaCl + H2O
Complete the statement by filling the gaps using appropriate term from the terms given in the bracket.
(slow, coloured, arrow, fast, smell, milky, physical, product, chemical, reactant, covalent, ionic, octet, duplet, exchange, sharing, equality sign)
Rusting of iron is a ______ chemical change.
Show with the help of diagram of electronic configuration how the following compound is formed from the constituent atoms.
Sodium chloride
Give an example of a reaction where the following are involved:
Solution
Give an example of a reaction where the following are involved
Catalyst
Give reason for the following:
Molybdenum is used in the manufacture of ammonia.
Give reason for the following:
Blue solution of copper sulphate changes to green when a piece of iron is added to this solution.
What is a chemical change? Give two examples of chemical change?
Complete and balance the following reaction:
NaCl(aq) + AgNO3(aq) →
State the original colour of the following substance and colour of residue obtained after heating.
Ammonium dichromate
What do you observe when H2S is passed through a lead nitrate solution.
Select the correct answer for the following options:
The pale blue precipitated obtained when copper [II] sulphate reacts with sodium hydroxide.
Complete the table given below.
| Addition of dil. H2SO4 to KHCO3 | Name of residue obtained |
Explain the term chemical reaction with special reference to reactants and products.
Select the correct answer from the options given below:
State the gaseous product formed, when
An active metal reacts with dilute sulphuric acid.
Select the correct answer from the options given below:
State the gaseous product formed, when
An ammonium salt reacts with an alkali.
Higher order Thinking question
Peeled and unpeeled banana does not look the same. Does that mean peeling banana is a chemical change?
Limestone contains ______ mainly.
______ change results in the change of the substance.
Classify the following processes into physical or chemical changes:
(i) Beating of aluminium metal to make aluminium foil.
(ii) Digestion of food.
(iii) Cutting of a log of wood into pieces.
(iv) Burning of crackers.
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.
What changes do you expect?
Magnesium + oxygen → magnesium oxide.
2Mg + O2 → 2Mg O
