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प्रश्न
Give reason .
A person suffering from acidity is advised to take an antacid.
उत्तर
An antacid neutralizes stomach acidity.
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संबंधित प्रश्न
How would you show that setting of curd is a chemical change?
How do the following help in bringing about a chemical change?
pressure.
Classify the following reaction as combination, decomposition, displacement, precipitation and neutralization. Also balance the equation.
\[\ce{NH3_{(g)} + HCl_{(g)} -> NH4Cl_{(s)}}\]
Write the missing reactants and products and balance the equations.
NaOH + ............... `→` NaCI + ...................
FILL IN THE BLANK
A .............. change is a temporary change.
MATCH THE COLUMNS
| 1 . `H_2` + `CI_2` `→` 2HCI | a. displacement reaction |
| 2. `2FeCI_3`+ `H_2` `→` `2FeCI_2` +2HCI` | b. addition of an electronegative redical |
| 3. Fe + `CuSO_4` `→``FeSO_4` +Cu` | c. removal of an electronegative redical |
| 4. `2H_2O` +`4NO_2`+`O_2` `→` `4HNO_3` | d.reduction by adding hydrogen |
| 5. 3Fe +`3CI_2` `→` `2FeCI_3` | e.electrolysis of water |
| 6. `FeCI_3`+ 3NaOH `→``Fe(OH)_3``↓`+NaCI | F.double decomposition,precipitation reaction |
| 7.`2H_2O` `→` `2H_2``↑`+`O_2` | e. combination or synthesis reaction |
Define chemical reaction.
A chemical equation is a statement that describes a chemical change in terms of
Name the type of chemical reaction shown by the following equation:
2Mg + O2 → 2MgO
Explain by writing a word equation.
Hard water gets softened on mixing with a solution of washing soda.
When electric current is passed through acidulated water ______ of water takes place.
Write the chemical reaction where the following changes are observed.
Precipitate is formed
Give reason for the following:
Blue solution of copper sulphate changes to green when a piece of iron is added to this solution.
Give an example of the following chemical changes.
A reaction where colour change is noticed.
Define:
Photochemical reaction
Give one example
Give a chemical test to distinguish between the following gases.
NH3 and HCl
Give reason for the following:
Electrolytic decomposition of water is a reaction involving change of state.
Name the following:
The type of change physical or chemical involved – ‘during respiration in human beings’.
NPK are the primary nutrients for plants.
Rusting of Iron: undesirable change:: Dead plants turn into manure: ______.
What is the use of indicator?
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
Iron benches kept in lawns and gardens get____________. It is a _________ change because a new _________ is formed.
Iron and rust are the same substances.
How can we prevent rusting?
Assertion (A): Cutting paper into very small pieces is an irreversible change.
Reason (R): Physical changes are always reversible.
When carbon dioxide is passed through lime water ______.
The reaction of H2 gas with oxygen gas to form water is an example of ______.
______ is the chemical name of slaked lime.
What is thermochemical reactions?
