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प्रश्न
Fill in the blank.
The formation of gas bubbles in a liquid during a reaction is called ......................
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उत्तर
The formation of gas bubbles in a liquid during a reaction is called effervesence
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संबंधित प्रश्न
Complete and balance the following chemical equations:
Fe `"SO"_4` + NaOH `→`
(aq.) (aq.)
Complete and balance the following chemical equation:
\[\ce{Pb(NO3)2 ->[Heat]}\]
MULTIPLE CHOICE QUESTIONS
Tick the most appropriate answer.
Compounds, which in their molten state allow an electric current to pass through them are called
- electrolytes
- non-electrolytes
- non-conductors
- none of these
TRUE \ FALSE
Electrolytic refining is a method in which a thin coating of a metal is done over another metal.
Write a short note on the information derived from a balanced chemical equation.
Fill in the blank:
The substances which undergo chemical change are called _______
| Reactants | Products | Type of chemical reaction |
| BaCl2(aq) + ZnSO4(aq) | H2CO3(aq) | Displacement |
| 2AgCl(s) | FeSO4(aq) + Cu(s) | Combination |
| CuSO4(aq) + Fe(s) | BaSO4↓ + ZnCl2(aq) | Decomposition |
| H2O(l) + CO2(g) | 2Ag(s) + Cl2(g) | Double displacement |
Give an example of a reaction where the following are involved
Catalyst
Write the chemical reaction where the following changes are observed.
Physical state is changed
Complete and balance the following reaction:
\[\ce{CuCO3 ->[\Delta]}\]
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 dilute sulphuric acid is added to the following:
Sodium Sulphide
Explain the term ‘chemical reaction’ with special reference to – ‘reactants’ and ‘products’.
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.
________ is a chemical substance which alters the speed of a chemical reaction.
When lithium metal is placed in hydrochloric acid, _______ gas is evolved.
Match the following:
| 1. | Sodium Chloride | a. | CaSO41/2H2O |
| 2. | Calcium sulphate dihydrate | b. | C2H5Oh |
| 3. | Magnesium sulphate hydrate | c. | CaSO4.2H2O |
| 4. | Calcium sulphate hemihydrate | d. | NaCl |
| 5. | Phenol | e. | MgSO4.H2O |
A student took a solution of copper sulphate in a beaker and put a clean iron nail into it and left it for about an hour.
Are these changes chemical in nature?
Vanaspati is obtained from vegetable oils by the addition of ______ to the oils.
______ are substances that speed up the process of a chemical change and it will not undergo any change during the course of the reaction.
