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Define an oxidation reaction.

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प्रश्न

Define an oxidation reaction.

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उत्तर

The chemical reaction in which reactants gain oxygen to form the corresponding oxide. Also, A chemical reaction in which reactants lose hydrogen to form a product is called oxidation.

Example: \[\ce{H2S + Cl -> 2HCl + S}\]

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अध्याय 7: Hydrogen - Exercise [पृष्ठ ९९]

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एस पी सिंग Concise Chemistry [English] Class 8 ICSE
अध्याय 7 Hydrogen
Exercise | Q 12.2 | पृष्ठ ९९

संबंधित प्रश्न

Define ‘redox reaction’. Give one example.


What is an oxidising agent?


Define corrosion.


What is meant by rust?


Identify the component oxidised in the following reaction:

\[\ce{H2S + Cl2 -> S + 2HCl}\]


Define the following in terms of gain or loss of hydrogen with one example:

Oxidation


When a magnesium ribbon is heated, it burns in air to form magnesium oxide. Write a balanced chemical equation for this reaction. Name

  1. substance oxidised, and
  2. substance reduced.

In the reaction represented by the following equation:

\[\ce{CuO_{(s)} + H2_{(g)} -> Cu_{(s)} + H2O_{(l)}}\]

  1. name the substance oxidised
  2. name the substance reduced
  3. name the oxidising agent
  4. name the reducing agent

You are given the following chemical equation:

\[\ce{Mg_{(s)} + CuO_{(s)} -> MgO_{(s)} + Cu_{(s)}}\]

This equation represents:


Fill in the blank

 Oxidation is the removal of ......................and addition of ....................


Define reduction.


Define redox reaction.


The electron releasing tendency of zinc is ______ than that of copper. 


Identify from the reaction the reactants that undergo oxidation and reduction.

\[\ce{NiO + H2 -> Ni + H2O}\]


Explain the following in term of gain or loss of oxygen with two examples.

Reduction


Compare hydrogen with alkali metals on the basis of:

Oxide formation 


In what respect does hydrogen differ from:

alkali metals


Give the general group study of hydrogen with reference to

burning


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?


Describe briefly the ionic concept of oxidation and reduction. Give an equation to illustrate.


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.

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.

H2+ Cl2→ 2HCl + S


Divide the following reactions into oxidation and reduction half-reaction:

Zn + Pb2+→ Pb + Zn 2+


Divide the following reactions into oxidation and reduction half-reaction:

Cl2 + 2Br- → Br2 + 2Cl-


Divide the above equation into oxidation and reduction half-reactions.


Name:

an oxidizing agent that does not contain oxygen.


Name:

a substance that will reduce aqueous Iron(III)ions to iron(II)ions.


Complete and balance the following equation:

CuO +__________→ Cu +___________


Explain the term reduction in term of addition and removal of oxygen/hydrogen with a suitable example.


Select the correct answer from the symbol in the bracket.

The element, which like hydrogen is a strong reducing agent.


When the positive charge on an ion increases or the negative charge on them decreases it is called as _______.


Balance the given chemical reaction as per the instructions below.

\[\ce{NaOH + H2SO4 -> Na2SO4 + H2O}\]

Oxidation means losing electrons then what is reduction?


Rusting of iron involves a chemical reaction which is a combination 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 - 

`"H"_2"O" + "F"_2 -> "HF" + "HOF"`


Identify the oxidising agent (oxidant) in the following reactions 

`"Pb"_3"O"_4 + 8"HCl" -> 3"PbCl"_2 + "Cl"_2 + 4"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?

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.


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.


Zinc liberates hydrogen gas when reacted with dilute hydrochloric acid whereas copper does not. Explain why?


A silver article generally turns black when kept in the open for a few days. The article when rubbed with toothpaste again starts shining.

  1.  Why do silver articles turn black when kept in the open for a few days? Name the phenomenon involved.
  2. 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.


Mention some oxidation reactions that occur in daily life.


The formation of brown colour on the freshly unit surface of vegetables and fruits is because ______ of organic compounds present in them.


The sum of the oxidation number of all atoms in a compound is ______.


Identify the following reactions as oxidation/reduction/redox reaction

2Mg +O2 → 2MgO


What are redox reactions? Give examples.


Define oxidation number.


Find the oxidation number of the element in the following compound.

N in NH3


Answer the questions based on the equation below:

\[\ce{CH3 - CH2 - OH ->[{[O]}][K2Cr2O7/H2SO4] CH3 - COOH}\]

  1. What type of reaction is it?
  2. What is the role of the chemical written on the arrow?
  3. Give one example of one such type of chemical as in answer (b).

A reddish brown metal used in electrical wires when powdered and heated strongly turns black. When hydrogen gas is passed over this black substance, it regains its original colour. Based on this information answer the following questions:

  1. Name the metal and the black substance formed.
  2. Write balanced chemical equations for the two reactions involved in the above information

The oxidizing agent in the equation \[\ce{S + 2H2SO4 -> 3SO2 + 2H2O}\] is ______.


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