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प्रश्न
During the reaction of some metals with dilute hydrochloric acid, following observations are made.
The reaction of sodium metal is found to be highly explosive
Explain this observation giving suitable reason.
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उत्तर
Hydrogen gas is evolved when sodium metal (Na) is reacted with dilute HCl. The reaction is of exothermic nature. Therefore, hydrogen catches fire accompanied by explosion.
`2"Na"("s") + 2"HCl" ("aq") -> 2"NaCl"("aq") + "H"_2("g")`
Remember : Sodium metal as such does not catch fire. It is the hydrogen gas evolved which burns since the reaction is highly exothermic in nature.
संबंधित प्रश्न
Give an example of an oxidation reaction.
Define the following in terms of gain or loss of hydrogen with one example:
Oxidation
MULTIPLE CHOICE QUESTIONS
The process of adding oxygen to a substance is called
- oxidation.
- reduction.
- displacement.
- hydrogenation.
Why this reaction is considered a reversible reaction?
Divide the following reactions into oxidation and reduction half-reaction:
Zn + Cu2+ → Cu + Zn 2+
Name:
a substance that will reduce aqueous Iron(III)ions to iron(II)ions.
State the condition and give balanced equation for the conversion of coke to water gas.
Identify the following reactions as oxidation or reduction
- Na → Na+ + e
- Fe3+ + 2 e- → Fe+
Find the oxidation number of the elements in the following compounds.
- C in CO2
- Mn in MnSO4
- N in HNO3
The process of reduction involves ____________.
In the reaction of iron with copper sulphate solution:
CuSO4 + Fe → Cu + FeSO4
Which option in the given table correctly represents the substance oxidized and the reducing agent?
| OPTION | Substance Oxidized | Reducing Agent |
| A | Fe | Fe |
| B | Fe | FeSO4 |
| C | Cu | Fe |
| D | CuSO4 | Fe |
Identify the oxidising agent (oxidant) in the following reactions.
`"CuO" + "H"_2 -> "Cu" + "H"_2"O"`
Which among the following are physical or chemical change?
Heating of an iron rod to red hot
During the reaction of some metals with dilute hydrochloric acid, following observations are made.
The temperature of the reaction mixture rises when aluminium (Al) is added.
Explain this observation giving suitable reason.
On adding a drop of barium chloride solution to an aqueous solution of sodium sulphite, white precipitate is obtained :
- Write a balanced chemical equation for the reaction involved.
- What other name can be given to this precipitation reaction?
- On adding dilute hydrochloric acid to the reaction mixture, white precipitate disappears. Why?
The tendency of atoms to have eight electrons in the outer shell is known as ______.
Choose the odd one out and write the reason:
Identify the type of chemical reaction given below:
\[\ce{2Mg + O2 -> 2MgO}\]
State the change in colour observed in following case mentioning the reason:
Copper powder is strongly heated in air.
