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प्रश्न
Give one example that illustrates the following characteristics of a chemical reaction:
Change in state
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उत्तर
The reaction between hydrogen sulphide and chlorine (both gases) produces sulphur (solid) and hydrogen chloride (gas).
\[\ce{\underset{Hydrogen sulphide}{H2S_{(g)}} + \underset{Chlorine}{Cl2_{(g)}}-> \underset{Hydrogen chloride}{2HCl_{(g)}} + \underset{(yellow solid)}{\underset{Sulphur}{S_{(s)}}}}\]
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संबंधित प्रश्न
The chemical name of baking soda is ______.
How do the following help in bringing about a chemical change?
light.
How do the following help in bringing about a chemical change?
catalyst .
Name three biochemical catalysts found in the human body.
Fill in the blank
A catalyst either ................or ............... the rate of a chemical change but itself remains ............... at the end of the reaction.
Write the missing reactants and products and balance the equations.
................+ HCI `→` NaCI + `"H"_2"O"` + .........................
Fill in the blank:
The basic conditions necessary for a chemical reaction is _______
Explain by writing a word equation.
Bubbles are seen on adding lemon juice to baking soda.
Give an example of the following chemical change.
A reaction where colour change is noticed
Multiple choice:
Thermal decomposition of sodium carbonate will produce
Select the correct answer for the following options:
The black residue obtained on heating copper carbonate.
Select the correct answer for the following options:
The pale blue precipitated obtained when copper [II] sulphate reacts with sodium hydroxide.
Give reason for the following:
Electrolytic decomposition of water is a reaction involving change of state.
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 water to quicklime.
Complete the table given below.
| Addition of dil. H2SO4 to FeS | Odour of gas evolved |
Complete the table given below.
| Addition of dil. H2SO4 to zinc | Test for gas evolved |
________ is a chemical substance which alters the speed of a chemical reaction.
Rusting of Iron: undesirable change:: Dead plants turn into manure: ______.
______ change results in the change of the substance.
Classify the following processes into physical or chemical changes:
- Beating of aluminium metal to make aluminium foil.
- Digestion of food.
- Cutting of a log of wood into pieces.
- Burning of crackers.
