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प्रश्न
Define corrosion.
Define the following term:
Corrosion
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उत्तर १
When a metal is attacked by substances around it, such as moisture, acids, etc., it is said to corrode, and this process is called corrosion.
उत्तर २
Corrosion is an electrochemical process in which a metal is oxidised to a metal oxide or another salt of the metal by losing electrons to oxygen or another electronegative element, forming a coating on the metal surface.
संबंधित प्रश्न
Define ‘redox reaction’. Give one example.
A shiny brown-coloured element ‘X’ on heating in air becomes black in colour. Name the element ‘X’ and the black-colored compound formed.
What is meant by rust?
What are anti-oxidants?
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.
Is oxidation an exothermic or an endothermic reaction?
Explain the following in terms of gain or loss of oxygen with one example:
Reduction
Define the following in terms of gain or loss of hydrogen with one example:
Reduction
In the context of redox reactions, the removal of hydrogen from a substance is known as ______.
You are given the following chemical equation:
\[\ce{Mg_{(s)} + CuO_{(s)} -> MgO_{(s)} + Cu_{(s)}}\]
This equation represents:
Define redox reaction.
TRUE \ FALSE
Hydrogen is a good oxidizing agent.
Explain the following in term Reduction of gain or loss of oxygen with two example.
Identify from the reaction the reactants that undergo oxidation and reduction.
Fe + S → FeS
Give the general group study of hydrogen with reference to
reducing power
Compare hydrogen and halogens on the basis of:
reaction with oxygen
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 whether the following conversion is oxidation or reduction:
K → K+ + e-
State whether the following conversion is oxidation or reduction:
2Cl- - e-→ Cl2
Divide the following reactions into oxidation and reduction half-reaction:
Zn + Pb2+→ Pb + Zn 2+
Write the equation in the ionic form
CuSO4(aq) + Fe(s)→ FeSO4(aq) + Cu(s)
For the reaction PbO + H2→ Pb + H2O, which of the following statements is wrong?
Name:
a substance that will reduce aqueous Iron(III)ions to iron(II)ions.
Name:
a gas that is oxidizing as well as a reducing agent.
Name:
a solid that is an oxidizing agent.
State a reason why, when hydrogen is passed over heated copper oxide, the resultant product formed, differs in colour from the original reactant.
State what is oxidising agent. Give an example of oxidising agent in the gaseous, liquid, and solid form.
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:
In the reaction of iron with copper sulphate solution:
CuSO4 + Fe → Cu + FeSO4
Which option in the given table correctly represents the substance oxidized and the reducing agent?
| OPTION | Substance Oxidized | Reducing Agent |
| A | Fe | Fe |
| B | Fe | FeSO4 |
| C | Cu | Fe |
| D | CuSO4 | Fe |
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
`2"Mg" + "O"_2 -> 2"MgO"`
Identify the oxidising agent (oxidant) in the following reactions
`3"Fe" + 4"H"_2"O" -> "Fe"_3"O"_4 + 4"H"_2`
Grapes hanging on the plant do not ferment but after being plucked from the plant can be fermented. Under what conditions do these grapes ferment? Is it a chemical or a physical change?
Which among the following are physical or chemical change?
Evaporation of petrol
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?
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.
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 ______.
The sum of the oxidation number of all atoms in a compound is ______.
Identify the following reactions as oxidation/reduction/redox reaction
Zn + CuSO4 → Cu + ZnSO4
What is rancidity?
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.
A1 in AlCl3
Identify the type of chemical reaction given below:
\[\ce{2Mg + O2 -> 2MgO}\]
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.
The metallic oxide which can be reduced by using common reducing agents is ______.
