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प्रश्न
State what you would observe when the following substance is heated in a glass test tube Copper (II) carbonate Red lead .
उत्तर
CuCO3 → CuO + CO2 ↑
The blue-green powder turns black and a colourless gas is evolved which extinguishes a burning flame.
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संबंधित प्रश्न
Complete and balance the following chemical equations:
N2 + O2 →
Complete and balance the following chemical equations:
Zn + `"H"_2"SO"_4` `→`
(dil)
Fill in the blank
A catalyst either ................or ............... the rate of a chemical change but itself remains ............... at the end of the reaction.
MULTIPLE CHOICE QUESTIONS
Tick the most appropriate answer
Which of the following is a reducing agent?
- oxygen
- chlorine
- hydrogen
- none of these
TRUE \ FALSE
Ammonia is a good oxidizing agent.
Name three reducing agents ?
Differentiate between in Chemical reaction and chemical equation.
Fill in the blank:
The basic conditions necessary for a chemical reaction is _______
Write true or false.
A chemical equation gives only qualitative information of a chemical reaction.
Explain the following reaction with one suitable example of Double decomposition reaction.
A solution of a substance ‘X’ is used for white washing Name the substance ‘X’ and write its formula.
Define the following terms
Precipitate
Give an example of a reaction where the following are involved
Light
Give reason for the following:
Silver nitrate solution is kept in coloured bottles.
Explain,giving one example of the following chemical changes:
Reversible reaction
Complete the following table and write your observations.
|
Hydrogen sulphide |
Ammonia |
Sulphur dioxide |
Hydrogen chloride |
|
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Shake the gas with red litmus solution |
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Shake the gas with blue litmus solution |
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Apply a burning splint to a gas |
Give a chemical test to distinguish between the following gases.
NH3 and HCl
Explain the term ‘chemical reaction’ with special reference to – ‘reactants’ and ‘products’.
What is a chemical reaction?
Give balanced equation for the following conversion affected by heat alone on the substance:
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______ change results in the change of the substance.
Chemists identify gypsum as a natural indicator.
Write word equations for two chemical reactions with the help of materials given in the box.
Air, copper sulphate, iron, vinegar, iron oxide, carbon dioxide, iron sulphate, copper, lime water, water
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?
Vanaspati is obtained from vegetable oils by the addition of ______ to the oils.
Magnesium + oxygen → magnesium oxide.
2Mg + O2 → 2Mg O
Write the chemical reaction of baking soda with lemon.
Write a note on the following:
Curdling of milk
Write the effects of chemical reactions.
