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प्रश्न
What kind of a change is associated with decaying of a plants?
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उत्तर
Decaying plants is associated with slow change and chemical change.
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संबंधित प्रश्न
How do the following help in bringing about a chemical change?
light.
MULTIPLE CHOICE QUESTIONS
Tick the most appropriate answer.
Which one of the following alters the rate of the chemical reaction without itself undergoing any change?
- temperature and Pressure
- concentration of reactants
- presence of catalyst
- none of these
State the conditions necessary for a chemical change or reaction.
Give an example of a reaction where the following are involved
Catalyst
Name the gases which turn moist red litmus blue.
What is observed in performing the following :
| Hydrogen | Oxygen | Carbon dioxide | Chlorine | |
| Litmus test | ||||
| Apply a burning splint to the gas | ||||
| Colour of gas | colourless | colourless | colourless | greenish-yellow |
| Odour of gas |
What do you observe when H2S is passed through a lead nitrate solution.
Select the correct answer for the following options:
The basic gas obtained when two gases react in presence of a catalyst and the reaction is exothermic.
Give balanced equation for the following conversion affected by heat alone on the substance:
Zinc nitrate to nitrogen dioxide
Complete the table given below.
| Addition of dil. H2SO4 to FeS | Odour of gas evolved |
Explain with the help of balanced equations, how precipitation reactions are used for identifying the positive radicals in three different salts, each having a different cation [positive ion].
Name the solid residual product formed reaction and state its colour during – thermal decomposition of the following substance.
Zinc carbonate.
_____ is the basic material to manufacture urea.
Silver metal can displace hydrogen gas from nitric acid.
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.
Write some materials prepared by chemical changes.
Classify each of the following, as a physical or a chemical change. Give reasons.
(a) Drying of a shirt in the sun.
(b) Rising of hot air over a radiator.
(c) Burning of kerosene in a lantern.
(d) Change the colour of black tea by adding lemon juice to it.
(e) Churning of milk cream to get butter.
Give two examples for the following case:
Chemical changes
Rusting of iron is ______.
Write the chemical reaction of baking soda with lemon.
