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प्रश्न
Identify from the reaction the reactants that undergo oxidation and reduction.
2Mg + O2 → 2MgO
\[\ce{2Mg + O2 ->[\Delta] 2MgO}\]
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उत्तर १
In a reaction, magnesium is changing to magnesium oxide. That means, oxygen is being added to magnesium. Addition of oxygen to a substance is called oxidation, so magnesium undergoes oxidation.
उत्तर २
Mg undergoes oxidation and O2 undergoes reduction.
संबंधित प्रश्न
Explain the following in term Oxidation of gain or loss of oxygen with two example.
Why is photosynthesis considered an endothermic reaction?
In the following reaction between lead sulphide and hydrogen peroxide:
\[\ce{PbS_{(s)} + 4H2O2_{(aq)} -> PbSO4_{(s)} + 4H2O_{(l)}}\]
- Which substance is reduced?
- Which substance is oxidised?
Give an example of an oxidation reaction.
Fill in the blank
In redox reaction oxidation and reduction occur ............................
MULTIPLE CHOICE QUESTIONS
The process of adding oxygen to a substance is called
- oxidation.
- reduction.
- displacement.
- hydrogenation.
Electrolysis is a redox process. Explain.
Explain the following in term of gain or loss of oxygen with two examples.
Reduction
In what respect does hydrogen differ from:
alkali metals
A metal oxide that is reduced by hydrogen is
For the reaction PbO + H2→ Pb + H2O, which of the following statements is wrong?
Complete and balance the following equation:
H2 + S → ___________
Complete and balance the following equation:
\[\ce{K + H2O -> }\]________+ ________
With reference to oxidation & reduction reaction – complete the statement given by filling in the blanks with only the words (a) Addition (b) Removal.
‘Oxidation is a chemical reaction involving ____ of oxygen to a substance or ____ of hydrogen from a substance. Reduction on the otherhand involves ____ of hydrogen to a substance or ____ of oxygen from a substance.
Explain the term oxidation in term of addition and removal of oxygen/hydrogen with a suitable example.
Explain the term reduction in term of addition and removal of oxygen/hydrogen with a suitable example.
State what is oxidising agent. Give an example of oxidising agent in the gaseous, liquid, and solid form.
Give two tests for a reducing agent.
Balance the given chemical reaction as per the instructions below.
\[\ce{NaOH + H2SO4 -> Na2SO4 + H2O}\]
Oxidation means losing electrons then what is reduction?
Oxidising agents are also called as ______ because they remove electrons form other substances.
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.
Identify the reducing agent in the following reactions
`4"NH"_3 + 5"O"_2 -> 4"NO" + 6"H"_2"O"`
Identify the oxidising agent (oxidant) in the following reactions
`2"Mg" + "O"_2 -> 2"MgO"`
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 formation of brown colour on the freshly unit surface of vegetables and fruits is because ______ of organic compounds present in them.
The tendency of atoms to have eight electrons in the outer shell is known as ______.
Identify the following reactions as oxidation/reduction/redox reaction
CuO+H2 → Cu+H2O
What are redox reactions? Give examples.
What is rancidity?
Find the oxidation number of the element in the following compound.
Ca in CaH2
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.
It is recommended to use air tight containers for storing oil for a long time.
State the change in colour observed in following case mentioning the reason:
Copper powder is strongly heated in air.
The oxidizing agent in the equation \[\ce{S + 2H2SO4 -> 3SO2 + 2H2O}\] is ______.
The metallic oxide which can be reduced by using common reducing agents is ______.
