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प्रश्न
The chemical formula for rust is.............. .
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उत्तर
The chemical formula for rust is Fe2O3. x H2O
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संबंधित प्रश्न
Define ‘redox reaction’. Give one example.
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.
What is meant by rust?
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?
Is oxidation an exothermic or an endothermic 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
In the context of redox reactions, the removal of hydrogen from a substance is known as ______.
The process of respiration is ______.
You are given the following chemical equation:
\[\ce{Mg_{(s)} + CuO_{(s)} -> MgO_{(s)} + Cu_{(s)}}\]
This equation represents:
Indicate which of the following statement is true and which is false:
The removal of hydrogen from a substance is called reduction.
Name the following:
The process in which oxygen is added or hydrogen is removed.
Define an oxidation reaction.
Define reduction.
Identify the substances that are oxidised and the substances that are reduced in the following reaction.
\[\ce{CuO_{(s)} + H2_{(g)} -> Cu_{(s)} + H2O_{(l)}}\]
The electron releasing tendency of zinc is ______ than that of copper.
Identify from the reaction the reactants that undergo oxidation and reduction.
Fe + S → FeS
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
Compare hydrogen and halogens on the basis of:
reaction with oxygen
Why zinc and aluminium are considered to have a unique nature. Give balanced equations to support your answer.
Describe briefly the ionic concept of oxidation and reduction. Give an equation to illustrate.
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.
H2S + 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-
Reacting with water, an active metal produces
Which of the following statements about hydrogen is incorrect?
Choose terms from the options given in brackets to complete this sentence.
When CuO reacts with hydrogen,………………… is reduced and ……………….is oxidized to ………………….
(CuO, H2, Cu, H2O)
Name:
an oxidizing agent that does not contain oxygen.
Name:
a gas that is oxidizing as well as a reducing agent.
With reference to oxidation & reduction reaction – complete the statement given by filling in the blanks with only the words (a) Addition (b) Removal.
‘Oxidation is a chemical reaction involving ____ of oxygen to a substance or ____ of hydrogen from a substance. Reduction on the otherhand involves ____ of hydrogen to a substance or ____ of oxygen from a substance.
Find the oxidation number of the elements in the following compounds.
- C in CO2
- Mn in MnSO4
- N in HNO3
Rusting of iron involves a chemical reaction which is a combination of:
Oxidation is a process which involves ____________.
\[\ce{MnO2 + 4HCl -> + 2H2O + Cl2}\]
Identify the substance oxidized in the above equation.
When Ag is exposed to air it gets a black coating 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 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?
Burning of Liquefied Petroleum Gas (LPG)
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?
Write a short note on oxidizing and reducing agents.
Oxidizing agents are otherwise called ______.
The tarnishing of metals is due to the formation of ______.
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
Find the oxidation number of the element in the following compound.
Ca in CaH2
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.
Metals are good ______.
