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प्रश्न
Fill in the blank.
The formation of gas bubbles in a liquid during a reaction is called ......................
उत्तर
The formation of gas bubbles in a liquid during a reaction is called effervesence
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संबंधित प्रश्न
State whether the following statement is true or false. In case a statement is false, write the corrected statement.
Formation of manure from leaves is a physical change.
The gas we use in the kitchen is called liquefied petroleum gas (LPG). In the cylinder, it exists as a liquid. When it comes out from the cylinder it becomes a gas (Change − A), then it burns (Change − B). The following statements pertain to these changes. Choose the correct one.
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
TRUE \ FALSE
Weak electrolytes dissociate partially in their aqueous or fused state.
What are biocatalysts ?
True or false
New substances are formed in a chemical change.
Fill in the blank
A change in which the substance can be brought back to its original state is called a _______ change.
Name the type of chemical reaction shown by the following equation:
2Mg + O2 → 2MgO
Choose the correct option from the bracket and explain the statement giving reason.
(Oxidation, displacement, electrolysis, reduction, zinc, copper, double displacement, decomposition)
To prevent rusting, a layer of ______ metal is applied on iron sheets.
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)
An ______ is drawn in between the reactants and products while writing the equation for a chemical reaction.
Multiple choice:
Which of the following is not a characteristic of a chemical change?
Multiple choice:
A reaction of a type: AB + CD → AD + CD, involves
Give an example of the following chemical changes.
A reaction where colour change is noticed.
Name: A brown gas
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 |
Give a word equation for the following reaction.
Two solids which combine on heating, to give a liquid.
Give a word equation for the following reaction.
A compound which on heating shows – colour change from brown to yellow.
Give reason for the following:
The catalytic oxidation of sulphur dioxide to sulphur trioxide is represented by a double arrow {⇌}
between the reactants and products, formed in the chemical reaction.
Name the following:
The products obtained during ‘photosynthesis’ – which is a chemical change.
State the following reaction represent oxidation or reduction.
\[\ce{Cl- ->Cl}\]
Give a suitable example with an equation to show the representation of a chemical reaction.
What happens when cane sugar is strongly heated? Mention any two changes in it.
Assertion: The formation of iron oxide from iron is a chemical change.
Reason: For the rust to form from iron, it must be exposed to air and water.
Burning of paper is a ______ change.
Limestone contains ______ mainly.
Can a nickel spatula be used to stir copper sulphate solution? Justify your answer.
The chemical name of baking soda is sodium bicarbonate.
Why is spoiling food a chemical change?
When carbon dioxide is passed through lime water ______.
