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प्रश्न
Circle the odd one out. Give reason for your choice
विकल्प
Growth of a child
Blinking of eye
Rusting
Germination of a seed
उत्तर
Rusting
Reason: Rusting is undesirable change. Others three are desirable changes.
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संबंधित प्रश्न
Fill in the blank
A catalyst either ................or ............... the rate of a chemical change but itself remains ............... at the end of the reaction.
What are oxides ?
TRUE \ FALSE
Copper can displace iron from iron sulphate.
What are the characteristics of a chemical reaction ? A chemical reaction is characterised by an irreversible change in which a new substance is formed.
Fill in the blank
A new substance is formed in a _______ change.
Name the type of chemical reaction shown by the following equation:
CaCO3 → CaO + CO2
Complete the statement by filling the gaps using appropriate term from the terms given in the bracket.
(slow, coloured, arrow, fast, smell, milky, physical, product, chemical, reactant, covalent, ionic, octet, duplet, exchange, sharing, equality sign)
The spoiling of food is a chemical change which is recognized from the generation of certain ______ due to it.
Complete the statement by filling the gaps using appropriate term from the terms given in the bracket.
(slow, coloured, arrow, fast, smell, milky, physical, product, chemical, reactant, covalent, ionic, octet, duplet, exchange, sharing, equality sign)
Oxygen is a ______ in respiration.
What do you observe? When
Water is added to the quick lime.
Give a chemical test to distinguish between the following gases.
SO2 and Cl2
Select the correct answer for the following options:
The black residue obtained on heating copper carbonate.
State whether the following reaction is oxidation or reduction.
\[\ce{Na->Na+}\]
Explain the term chemical reaction with special reference to reactants and products.
Select the correct answer from the options given below:
State the gaseous product formed, when
An active metal reacts with dilute sulphuric acid.
What kind of a change is associated with decaying of a plants?
Limestone contains ______ mainly.
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.
The water we drink is a combination of hydrogen and oxygen.
Which of the following are chemical changes?
(i) Decaying of wood
(ii) Burning of wood
(iii) Sawing of wood
(iv) Hammering of a nail into a piece of wood
Which of the following is/are true when milk changes into curd?
- Its state is changed from liquid to semi-solid.
- It changes colour.
- It changes the taste.
- The change cannot be reversed.
Choose the correct option from below:
