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प्रश्न
Identify from the following reaction the reactants that undergo oxidation and reduction.
\[\ce{2Ag2O → 4 Ag + O2 \uparrow}\]
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उत्तर
In a reaction, silver oxide is changing to silver. That is, oxygen is being removed from silver oxide. Removal of oxygen from a substance is called reduction, so silver oxide undergoes reduction.
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संबंधित प्रश्न
What is an oxidising agent?
A shiny brown-coloured element ‘X’ on heating in air becomes black in colour. Name the element ‘X’ and the black-colored compound formed.
Identify the component oxidised in the following reaction:
\[\ce{H2S + Cl2 -> S + 2HCl}\]
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.
Explain the following in terms of gain or loss of oxygen with one example:
Oxidation
When copper powder is heated strongly in air, it forms copper oxide. Write a balanced chemical equation for this reaction. Name
- substance oxidised, and
- substance reduced.
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 context of redox reactions, the removal of hydrogen from a substance is known as ______.
The process of respiration is ______.
Indicate which of the following statement is true and which is false:
The removal of hydrogen from a substance is called reduction.
Define redox reaction.
TRUE \ FALSE
Hydrogen is a good oxidizing agent.
Identify the substances that are oxidised and the substances that are reduced in the following reaction.
\[\ce{CuO_{(s)} + H2_{(g)} -> Cu_{(s)} + H2O_{(l)}}\]
Explain the following in term Reduction of gain or loss of oxygen with two example.
The colours of aqueous solutions of CuSO4 and FeSO4 as observed in the laboratory are:
(A) pale green and light blue respectively
(B) light blue and dark green respectively
(C) dark blue and dark green respectively
(D) dark blue and pale green respectively
In what respect does hydrogen differ from:
alkali metals
Why zinc and aluminium are considered to have a unique nature. Give balanced equations to support your answer.
State, giving reason, whether the substances printed in bold letters have been oxidized or reduced.
H2S + Cl2→ 2HCl + S
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:
Cu2+ + 2 e-→ Cu
In the following reaction: A+ + B → A + B+. Write half-reactions for this reaction and name:
- oxidizing agent
- substance oxidized
- reducing agent
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:
Zn + Cu2+ → Cu + Zn 2+
Write the equation in the ionic form
CuSO4(aq) + Fe(s)→ FeSO4(aq) + Cu(s)
A metal oxide that is reduced by hydrogen is
Which of the following statements about hydrogen is incorrect?
For the reaction PbO + H2→ Pb + H2O, which of the following statements is wrong?
Complete and balance the following equation:
Zn +_________________→ZnCl2 + H2
Complete and balance the following equation:
CuO +__________→ Cu +___________
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.
When the positive charge on an ion increases or the negative charge on them decreases it is called as _______.
Identify the following reactions as oxidation or reduction
- Na → Na+ + e
- Fe3+ + 2 e- → Fe+
Rusting of iron involves a chemical reaction which is a combination of:
\[\ce{MnO2 + 4HCl -> + 2H2O + Cl2}\]
Identify the substance oxidized in the above equation.
Select the oxidising agent for the following reaction:
\[\ce{H2S + I2 -> 2HI + S}\]
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
`3"Fe" + 4"H"_2"O" -> "Fe"_3"O"_4 + 4"H"_2`
Identify the oxidising agent (oxidant) in the following reactions.
`"CuO" + "H"_2 -> "Cu" + "H"_2"O"`
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
During the reaction of some metals with dilute hydrochloric acid, following observations are made.
Silver metal does not show any change
Explain this observation giving suitable reason.
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.
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.
- 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 is a redox reaction?
The tendency of atoms to have eight electrons in the outer shell is known as ______.
Identify the following reactions as oxidation/reduction/redox reaction
Zn + CuSO4 → Cu + ZnSO4
What are redox reactions? Give examples.
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).
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 ______.
