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प्रश्न
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उत्तर
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Oxidation
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Reduction
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The chemical reaction in which reactants combine with oxygen atoms to form corresponding oxides is known as an oxidation reaction.
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The chemical reactions in which reactants gain hydrogen are called reduction reactions.
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The chemical reactions in which reactants lose hydrogen atoms to form products are called oxidation-reduction reactions.
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The reactions in which reactants lose oxygen atoms to form products are called reduction reactions.
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संबंधित प्रश्न
Define ‘redox reaction’. Give one example.
What is an oxidising agent?
Why does the colour of copper sulphate solution change when an iron nail is dipped in it?
Which of the statements about the reaction below are incorrect?
\[\ce{2PbO(s) + C(s) → 2Pb(s) + CO2(g)}\]
- Lead is getting reduced.
- Carbon dioxide is getting oxidised.
- Carbon is getting oxidised.
- Lead oxide is getting reduced.
What are anti-oxidants?
In the reaction represented by the equation:
\[\ce{MnO2 + 4HCl -> MnCl2 + 2H2O + Cl2}\]
- name the substance oxidised.
- name the oxidising agent.
- name the substance reduced.
- name the reducing agent.
Is oxidation an exothermic or an endothermic reaction?
Define the following in terms of gain or loss of hydrogen with one example:
Oxidation
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
Name the following:
The process in which oxygen is added or hydrogen is removed.
Explain the following in term Reduction of gain or loss of oxygen with two example.
How would you change a metal like Cu into its ions?
Give scientific reason.
It is reccommended to use air tight container for storing oil for long time.
Identify from the reaction the reactants that undergo oxidation and reduction.
Fe + S → FeS
Identify from the reaction the reactants that undergo oxidation and reduction.
2Mg + O2 → 2MgO
Give the general group study of hydrogen with reference to
reducing power
Compare hydrogen and halogens on the basis of:
reaction with oxygen
Why this reaction is considered a reversible reaction?
State, giving reason, whether the substances printed in bold letters have been oxidized or reduced.
PbO + CO → Pb + CO2
State whether the following conversion is oxidation or reduction:
PbO2 + SO2→ PbSO4
State whether the following conversion is oxidation or reduction:
2Cl- - e-→ Cl2
Write the equation in the ionic form
CuSO4(aq) + Fe(s)→ FeSO4(aq) + Cu(s)
Divide the above equation into oxidation and reduction half-reactions.
A metal oxide that is reduced by hydrogen is
Name:
a gas that is oxidizing as well as a reducing agent.
Complete and balance the following equation:
Zn +_________________→ZnCl2 + H2
Explain the term redox reaction with an example involving the reaction of hydrogen sulphide with chlorine.
Give two tests for a reducing agent.
Oxidising agents are also called as ______ because they remove electrons form other substances.
Rusting of iron involves a chemical reaction which is a combination of:
Oxidation is a process which involves ____________.
\[\ce{MnO2 + 4HCl -> + 2H2O + Cl2}\]
Identify the substance oxidized in the above equation.
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"`
Identify the reducing agent in the following reactions
`"Fe"_2"O"_3 + 3"CO" -> 2"Fe" + 3"CO"_2`
Identify the reducing agent in the following reactions
`2"H"_2 + "O"_2 -> 2"H"_2"O"`
Identify the oxidising agent (oxidant) in the following reactions
`"CuSO"_4 + "Zn" -> "Cu" + "ZnSO"_4`
Which among the following are physical or chemical change?
Evaporation of petrol
Which among the following are physical or chemical change?
Heating of an iron rod to red hot
Which among the following are physical or chemical change?
Curding of milk
During the reaction of some metals with dilute hydrochloric acid, following observations are made.
Some bubbles of a gas are seen when lead (Pb) is reacted with the acid.
Explain this observation giving suitable reason.
Why do we store silver chloride in a dark coloured bottle?
A silver article generally turns black when kept in the open for a few days. The article when rubbed with toothpaste again starts shining.
- Why do silver articles turn black when kept in the open for a few days? Name the phenomenon involved.
- Name the black substance formed and give its chemical formula.
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 tarnishing of metals is an example of ______ reaction.
______ is a metal that has a high resistance to corrosion.
Identify the following reactions as oxidation/reduction/redox reaction
CuO+H2 → Cu+H2O
What is rancidity?
Define oxidation number.
Find the oxidation number of the element in the following compound.
Zn in ZnSO4
When hydrogen gas is passed over black copper oxide, a reddish-coloured layer of copper is formed.
Answer the questions that follow based on this reaction.
- Write the equation.
- What type of reaction is it?
- Complete the blanks:
In this reaction, an oxygen atom goes away from CuO (copper oxide), which means that ______ of copper oxide takes place, whereas a hydrogen molecule takes up an oxygen atom and water (H2O) is formed, meaning ______ of hydrogen takes place.
Answer the questions based on the equation below:
\[\ce{CH3 - CH2 - OH ->[{[O]}][K2Cr2O7/H2SO4] CH3 - COOH}\]
- What type of reaction is it?
- What is the role of the chemical written on the arrow?
- Give one example of one such type of chemical as in answer (b).
In the redox reaction:
MnO2 + 4HCl → MnCl2 + 2H2O + Cl2
Metals are good ______.
