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प्रश्न
Write chemical formula for rust.
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उत्तर
Chemical formula for rust: Fe2O3•xH2O
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संबंधित प्रश्न
Corrosion can be prevented by using ……………. solution.
Which of the statements about the reaction below are incorrect?
\[\ce{2PbO(s) + C(s) → 2Pb(s) + CO2(g)}\]
- Lead is getting reduced.
- Carbon dioxide is getting oxidised.
- Carbon is getting oxidised.
- Lead oxide is getting reduced.
Explain the following in term Oxidation of gain or loss of oxygen with two example.
Why is photosynthesis considered an endothermic reaction?
Identify the component oxidised in the following reaction:
H2S + Cl2 → S + 2HCl
Fill in the following blanks with suitable words:
The addition of oxygen to a substance is called ......... whereas removal of oxygen is called ........
When a magnesium ribbon burns in air with a dazzling flame and forms a white ash, is magnesium oxidised or reduced? Why?
When a magnesium ribbon is heated, it burns in air to form magnesium oxide. Write a balanced chemical equation for this reaction. Name (i) substance oxidised, and (ii) substance reduced.
In the reaction represented by the following equation:
CuO (s) + H2 (g) → Cu (s) + H2O (1)
(a) name the substance oxidised
(b) name the substance reduced
(c) name the oxidising agent
(d) name the reducing agent
In the context of redox reactions, the removal of hydrogen from a substance is known as:
(a) oxidation
(b) dehydration
(c) reduction
(d) dehydrogenation
In order to prevent the spoilage of potato chips, they are packed in plastic bags in an atmosphere of:
(a) Cl2
(b) H2
(c) N2
(d) O2
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.
Give scientific reason.
It is reccommended to use air tight container for storing oil for long time.
Compare hydrogen with alkali metals on the basis of:
Oxide formation
In what respect does hydrogen differ from:
alkali metals
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.
Mg + 2HCl → MgCl2 + H2
State whether the following conversion is oxidation or reduction:
Cu2+ + 2 e-→ Cu
Divide the following reactions into oxidation and reduction half-reaction:
Zn + Cu2+ → Cu + Zn 2+
Reacting with water, an active metal produces
For the reaction PbO + H2→ Pb + H2O, which of the following statements is wrong?
Name:
a substance that oxidizes concentrated HCl to chlorine.
Complete and balance the following equation:
H2 + S → ___________
Complete and balance the following equation:
CuO +__________→ Cu +___________
Complete and balance the following equation:
\[\ce{K + H2O -> }\]________+ ________
State a reason why, when hydrogen is passed over heated copper oxide, the resultant product formed, differs in colour from the original reactant.
Find the oxidation number of the elements in the following compounds.
- C in CO2
- Mn in MnSO4
- N in HNO3
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
`"V"_2"O"_5 + 5"Ca" -> 2"V" + 5"CaO"`
Which among the following are physical or chemical change?
Burning of Liquefied Petroleum Gas (LPG)
Why do we store silver chloride in a dark coloured bottle?
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.
Mention some oxidation reactions that occur in daily life.
The tarnishing of metals is an example of ______ reaction.
The sum of the oxidation number of all atoms in a compound is ______.
______ is a metal that has a high resistance to corrosion.
Identify the following reactions as oxidation/reduction/redox reaction
CuO+H2 → Cu+H2O
What are reducing agents? Give examples.
What are redox reactions? Give examples.
Define oxidation number.
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.
Mg in MgO
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.
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 ______.
