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प्रश्न
Identify from the reaction the reactants that undergo oxidation and reduction.
\[\ce{NiO + H2 -> Ni + H2O}\]
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उत्तर
In a reaction, nickel oxide is changing to nickel. That is, oxygen is being removed from nickel oxide. Removal of oxygen from a substance is called reduction, so nickel oxide undergoes reduction.
In a reaction, hydrogen is changing to H2O. That is, oxygen is being added to hydrogen. Addition of oxygen to a substance is called oxidation, so hydrogen undergoes oxidation.
The reactions in which oxidation and reduction take place simultaneously are called Redox reactions.
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संबंधित प्रश्न
Define ‘redox reaction’. Give one example.
The chemical formula for rust is.............. .
What are anti-oxidants?
Identify in the following reaction (a) the substance oxidised, and (b) the substance reduced:
\[\ce{ZnO + C -> Zn + CO}\]
Identify the component oxidised in the following reaction:
\[\ce{H2S + Cl2 -> S + 2HCl}\]
When SO2 gas is passed through saturated solution of H2S, the following reaction occurs:
\[\ce{SO2 + 2H2S -> 2H2O + 3S}\]
In this reaction, which substance is oxidised and which one is reduced?
When a magnesium ribbon burns in air with a dazzling flame and forms a white ash, is magnesium oxidised or reduced? Why?
Give an example of an oxidation reaction.
Is oxidation an exothermic or an endothermic reaction?
In the reaction represented by the following equation:
\[\ce{CuO_{(s)} + H2_{(g)} -> Cu_{(s)} + H2O_{(l)}}\]
- name the substance oxidised
- name the substance reduced
- name the oxidising agent
- name the reducing agent
In order to prevent the spoilage of potato chips, they are packed in plastic bags in an atmosphere of ______.
The process of respiration is ______.
Hydrogen burns with a ______ flame and ______ sound is heard.
Fill in the blank
Oxidation is the removal of ......................and addition of ....................
Explain the following in term Reduction of gain or loss of oxygen with two example.
Electrolysis is a redox process. Explain.
Identify from the reaction the reactants that undergo oxidation and reduction.
Fe + S → FeS
Compare hydrogen with alkali metals on the basis of:
Oxide formation
Describe briefly the ionic concept of oxidation and reduction. Give an equation to illustrate.
State, giving reason, whether the substances printed in bold letters have been oxidized or reduced.
PbO + CO → Pb + CO2
State, giving reason, whether the substances printed in bold letters have been oxidized or reduced.
Mg + 2HCl → MgCl2 + H2
State, giving reason, whether the substances printed in bold letters have been oxidized or reduced.
H2S + Cl2→ 2HCl + S
State whether the following conversion is oxidation or reduction:
2Cl- - e-→ Cl2
Divide the above equation into oxidation and reduction half-reactions.
A metal oxide that is reduced by hydrogen is
Name:
an oxidizing agent that does not contain oxygen.
Name:
a substance that will reduce aqueous Iron(III)ions to iron(II)ions.
Name:
a solid that is an oxidizing agent.
Complete and balance the following equation:
H2 + S → ___________
Give two tests for a reducing agent.
Select the correct answer from the symbol in the bracket.
The element, which like hydrogen is a strong reducing agent.
Rusting of iron involves a chemical reaction which is a combination of:
Which of the following statements about the given reaction are correct?
\[\ce{3Fe_{(s)} + 4H2O_{(g)} -> Fe3O4_{(s)} + 4H2_{(g)}}\]
(i) Iron metal is getting oxidised.
(ii) Water is getting reduced.
(iii) Water is acting as the reducing agent.
(iv) Water is acting as oxidising agent.
Oxidation is a process which involves ____________.
The process of reduction involves ____________.
When Ag is exposed to air it gets a black coating of ____________.
Identify the reducing agent in the following reactions
`4"NH"_3 + 5"O"_2 -> 4"NO" + 6"H"_2"O"`
Grapes hanging on the plant do not ferment but after being plucked from the plant can be fermented. Under what conditions do these grapes ferment? Is it a chemical or a physical change?
Which among the following are physical or chemical change?
Evaporation of petrol
Which among the following are physical or chemical change?
Burning of Liquefied Petroleum Gas (LPG)
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.
What happens when zinc granules are treated with dilute solution of H2SO4, HCl, HNO3, NaCl and NaOH Also write the chemical equations if reaction oçcurs.
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?
Mention some oxidation reactions that occur in daily life.
The tendency of atoms to have eight electrons in the outer shell is known as ______.
The tarnishing of metals is an example of ______ reaction.
______ is a metal that has a high resistance to corrosion.
Choose the odd one out and write the reason:
What are reducing agents? Give examples.
What are redox reactions? Give examples.
Define oxidation number.
In the redox reaction:
MnO2 + 4HCl → MnCl2 + 2H2O + Cl2
State whether the given chemical reaction is a redox reaction or not. Justify your answer.
\[\ce{MnO_2 + 4HCl->MnCl_2 +2H_2O + Cl_2}\]
Metals are good ______.
