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Question
What is meant by rust?
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Solution
Iron reacts with moist air to acquire a coating of a brown flaky substance called rust.
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RELATED QUESTIONS
Why does the colour of copper sulphate solution change when an iron nail is dipped in it?
Which of the statements about the reaction below are incorrect?
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CuO (s) + H2 (g) → Cu (s) + H2O (1)
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MULTIPLE CHOICE QUESTIONS
The process of adding oxygen to a substance is called
- oxidation.
- reduction.
- displacement.
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TRUE \ FALSE
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\[\ce{CuO_{(s)} + H2_{(g)} -> Cu_{(s)} + H2O_{(l)}}\]
Explain the following in term Reduction of gain or loss of oxygen with two example.
Identify from the following reaction the reactants that undergo oxidation and reduction.
\[\ce{2Ag2O → 4 Ag + O2 \uparrow}\]
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State whether the following conversion is oxidation or reduction:
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Divide the following reactions into oxidation and reduction half-reaction:
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Write the equation in the ionic form
CuSO4(aq) + Fe(s)→ FeSO4(aq) + Cu(s)
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)
State a reason why, when hydrogen is passed over heated copper oxide, the resultant product formed, differs in colour from the original reactant.
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Oxidation means losing electrons then what is reduction?
Identify the following reactions as oxidation or reduction
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Which of the following statements about the given reaction are correct?
\[\ce{3Fe_{(s)} + 4H2O_{(g)} -> Fe3O4_{(s)} + 4H2_{(g)}}\]
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(ii) Water is getting reduced.
(iii) Water is acting as the reducing agent.
(iv) Water is acting as oxidising agent.
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 |
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Identify the oxidising agent (oxidant) in the following reactions
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Identify the oxidising agent (oxidant) in the following reactions
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Identify the oxidising agent (oxidant) in the following reactions.
`"CuO" + "H"_2 -> "Cu" + "H"_2"O"`
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?
Heating of an iron rod to red hot
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.
Some bubbles of a gas are seen when lead (Pb) is reacted with the acid.
Explain this observation giving suitable reason.
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- What other name can be given to this precipitation reaction?
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Write a short note on oxidizing and reducing agents.
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______ is a metal that has a high resistance to corrosion.
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Choose the odd one out and write the reason:
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Find the oxidation number of the element in the following compound.
Zn in ZnSO4
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Mg in MgO
Identify the type of chemical reaction given below:
\[\ce{2Mg + O2 -> 2MgO}\]
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:
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- Write balanced chemical equations for the two reactions involved in the above information
Metals are good ______.
