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प्रश्न
Copper carbonate when heated, it turns :
पर्याय
Blue
Green
Black
Yellow
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उत्तर
Black.
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संबंधित प्रश्न
How do the following help in bringing about a chemical change?
heat.
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.
Miscible liquids having slightly different boiling points can be separated by the
- evaporation
- distillation
- fractional distillation
- sedimentation
Write true or false .
A black residue is formed when sugar is heated .
Give an example of a reaction where the following are involved
Light
Give an example of a reaction where the following are involved
Catalyst
Define a photochemical 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.
Complete the table given below.
| Heat on iodine crystals | Colour of vapours evolved |
State the following reaction represent oxidation or reduction.
\[\ce{Cl- ->Cl}\]
A chemical reaction is often accompanied by external indications or characteristics.
Complete the statement by filling in the blank with the correct word:
The reddish-brown precipitate obtained during a double decomposition precipitation reaction between an iron salt and alkali is __________.
Circle the odd one out. Give reason for your choice
What is the role of a catalyst in a chemical reaction?
Anaerobic bacteria digest animal waste and produce biogas (Change – A). The biogas is then burnt as fuel (Change – B). The following statements pertain to these changes. Choose the correct one.
Give an example of a chemical reaction for the following situation:
A change in colour is observed
Vanaspati is obtained from vegetable oils by the addition of ______ to the oils.
Match the following:
| Column I | Column II | ||
| 1. | Burning of coal | a. | Rusting |
| 2. | Painting of a surface | b. | Evaporation |
| 3. | Dipping iron in the water | c. | Chemical change |
| 4. | Salt from seawater | d. | Prevention of rusting |
Give an example where heat, light, and sound are produced during a chemical change.
Why is spoiling food a chemical change?
