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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.
संबंधित प्रश्न
What is an oxidising agent?
Explain the following in term Oxidation of gain or loss of oxygen with two example.
What is meant by rust?
Write the chemical formula of rust.
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?
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 one example of an oxidation-reduction reaction which is also a combination reaction.
When a magnesium ribbon is heated, it burns in air to form magnesium oxide. Write a balanced chemical equation for this reaction. Name
- substance oxidised, and
- substance reduced.
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
The process of respiration is ______.
Define reduction.
MULTIPLE CHOICE QUESTIONS
The process of adding oxygen to a substance is called
- oxidation.
- reduction.
- displacement.
- hydrogenation.
Electrolysis is a redox process. Explain.
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.
Give the general group study of hydrogen with reference to
reducing power
Why this reaction is considered a reversible reaction?
Why zinc and aluminium are considered to have a unique nature. Give balanced equations to support your answer.
Is it essential that oxidation and reduction must occur side by side in a chemical reaction? Explain
State, giving reason, whether the substances printed in bold letters have been oxidized or reduced.
Cl2 + H2S → 2HCl + S
State whether the following conversion is oxidation or reduction:
PbO2 + SO2→ PbSO4
State whether the following conversion is oxidation or reduction:
Cu2+ + 2 e-→ Cu
Divide the following reactions into oxidation and reduction half-reaction:
Zn + Cu2+ → Cu + Zn 2+
Divide the above equation into oxidation and reduction half-reactions.
Reacting with water, an active metal produces
Which of the following statements about hydrogen is incorrect?
Name:
a substance that will reduce aqueous Iron(III)ions to iron(II)ions.
Name:
a liquid that is an oxidizing agent as well as a reducing agent.
Name:
a gas that is oxidizing as well as a reducing agent.
Complete and balance the following equation:
H2 + S → ___________
Complete and balance the following equation:
CuO +__________→ Cu +___________
Explain the term oxidation in term of addition and removal of oxygen/hydrogen with a suitable example.
Explain the term redox reaction with an example involving the reaction of hydrogen sulphide with chlorine.
Give two test for an oxidising agent.
Select the correct answer from the symbol in the bracket.
The element, which like hydrogen is a strong reducing agent.
Write chemical formula for rust.
Oxidising agents are also called as ______ because they remove electrons form other substances.
The process of reduction involves ____________.
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 -
`"H"_2"O" + "F"_2 -> "HF" + "HOF"`
Identify the reducing agent in the following reactions
`"Fe"_2"O"_3 + 3"CO" -> 2"Fe" + 3"CO"_2`
Identify the oxidising agent (oxidant) in the following reactions
`3"Fe" + 4"H"_2"O" -> "Fe"_3"O"_4 + 4"H"_2`
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 reaction of sodium metal is found to be highly explosive
Explain this observation giving suitable reason.
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.
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.
You are provided with two containers made up of copper and aluminium. You are also provided with solutions of dilute HCl, dilute HNO3, ZnCl2 and water. In which of the above containers, can these solutions be kept?
The tendency of atoms to have eight electrons in the outer shell is known as ______.
The tarnishing of metals is due to the formation of ______.
Choose the odd one out and write the reason:
Define oxidation number.
Find the oxidation number of the element in the following compound.
Mg in MgO
Find the oxidation number of the element in the following compound.
N in NH3
Find the oxidation number of the element in the following compound.
A1 in AlCl3
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.
State whether the given chemical reaction is a redox reaction or not. Justify your answer.
\[\ce{MnO_2 + 4HCl->MnCl_2 +2H_2O + Cl_2}\]
