Advertisements
Advertisements
प्रश्न
Define corrosion.
Define the following term:
Corrosion
Advertisements
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
Corrosion can be prevented by using ……………. solution.
Why is photosynthesis considered an endothermic reaction?
Identify in the following reaction (a) the substance oxidised, and (b) the substance reduced:
\[\ce{ZnO + C -> Zn + CO}\]
In order to prevent the spoilage of potato chips, they are packed in plastic bags in an atmosphere of ______.
The process of respiration is ______.
Fill in the blank
In redox reaction oxidation and reduction occur ............................
Define reduction.
Identify the substances that are oxidised and the substances that are reduced in the following reaction.
\[\ce{CuO_{(s)} + H2_{(g)} -> Cu_{(s)} + H2O_{(l)}}\]
Identify from the reaction the reactants that undergo oxidation and reduction.
2Mg + O2 → 2MgO
Explain the following in term of gain or loss of oxygen with two examples.
Oxidation
In what respect does hydrogen differ from:
alkali metals
Give the general group study of hydrogen with reference to
burning
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.
Cl2 + H2S → 2HCl + S
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)
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:
Fe + H2O →___________+____________
Explain the term reduction in term of addition and removal of oxygen/hydrogen with a suitable example.
Give two tests for a reducing agent.
Oxidising agents are also called as ______ because they remove electrons form other substances.
\[\ce{MnO2 + 4HCl -> + 2H2O + Cl2}\]
Identify the substance oxidized in the above equation.
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
`"Pb"_3"O"_4 + 8"HCl" -> 3"PbCl"_2 + "Cl"_2 + 4"H"_2"O"`
Which among the following are physical or chemical change?
Curding of milk
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 is a redox reaction?
What are reducing agents? Give examples.
Find the oxidation number of the element in the following compound.
A1 in AlCl3
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:
- Name the metal and the black substance formed.
- Write balanced chemical equations for the two reactions involved in the above information
The metallic oxide which can be reduced by using common reducing agents is ______.
