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प्रश्न
Define chemical reaction.
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उत्तर
Any chemical change in matter that involves its transformation into one or more new substances is called a chemical reaction.
संबंधित प्रश्न
MULTIPLE CHOICE QUESTIONS
Tick the most appropriate answer.
Reduction reaction is the exact opposite of
- displacement reaction
- decomposition reaction
- oxidation reaction
- none of these
Fill in the blank:
The substances which undergo chemical change are called _______
Fill in the blank:
In some chemical reactions an insoluble ________ is formed when two solutions are mixed.
Write true or false :
No new substance is formed during a chemical reaction.
What is the reaction called when oxidation and reduction take place simultaneously? Explain with one example.
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)
Electron ______ is complete in each hydrogen in a hydrogen molecule.
Give an example of a reaction where the following are involved:
Close contact
Define an electrochemical reaction.
Name: A greenish-yellow gas.
Give a chemical test to distinguish between the following gases.
HCl and Cl2
Complete the table given below.
| Heat on Zinc nitrate | Colour of residue |
Complete the table given below.
| Addition of dil. H2SO4 to KHCO3 | Name of residue obtained |
Limestone contains ______ mainly.
A reaction between an acid and a base is called ______.
Chemists identify gypsum as a natural indicator.
Two chemical species X and Y combine together to form a product P which contains both X and Y
\[\ce{X + Y -> P}\]
X and Y cannot be broken down into simpler substances by simple chemical reactions. Which of the following concerning the species X, Y and P are correct?
(i) P is a compound
(ii) X and Y are compounds
(iii) X and Y are elements
(iv) P has a fixed composition
Classify the following as physical or chemical properties
Zinc dissolves in hydrochloric acid with the evolution of hydrogen gas.
If you leave a piece of iron in the open for a few days, it acquires a film of brownish substance, called rust.
Can you change rust back into iron by some simple method?
Define the following term:
Chemical change
Collect information about the types of fuels used for cooking in your area. Discuss with your teachers/parents/others which fuels are less polluting and why.
