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प्रश्न
A solution of a substance ‘X’ is used for white washing Name the substance ‘X’ and write its formula.
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उत्तर
Calcium oxide CaO
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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.
Iron pipes coated with zinc do not get rusted easily.
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 (i) positive catalysts and (ii) negative catalysts? Support your answer with one example for each of them.
Complete and balance the following chemical equations
Na + H2 O →
MULTIPLE CHOICE QUESTIONS
Tick the most appropriate answer.
Reduction is a chemical reaction in which there is
- removal of hydrogen
- removal of oxygen
- addition of oxygen
- none of these
TRUE \ FALSE
The evolution of a gas during a chemical reaction is shown by an arrow pointing downwards. True or false ?
Write a short note on the information derived from a balanced chemical equation.
Write true or false :
No new substance is formed during a chemical reaction.
Write true or false .
A black residue is formed when sugar is heated .
Balance the following equation :
Fe + H2O → Fe3O4 + H2
Name the type of chemical reaction shown by the following equation:
Fe + CuSO4 → FeSO4 + Cu
Distinguish by dilute sulphuric acid.
Copper and magnesium?
Give reason for the following:
The catalytic oxidation of sulphur dioxide to sulphur trioxide is represented by a double arrow {⇌}
between the reactants and products, formed in the chemical reaction.
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.
State the following reaction represent oxidation or reduction.
\[\ce{H->H+}\]
Name the solid residual product formed reaction and state its colour during – thermal decomposition of the following substance.
Ammonium dichromate.
Higher order Thinking question
A very hot glass on putting in cold water cracks. What does this change indicate?
Rusting of Iron: undesirable change:: Dead plants turn into manure: ______.
Write a note on the following:
Curdling of milk
Acid rain is a result of ______.
