Advertisements
Advertisements
Question
When the positive charge on an ion increases or the negative charge on them decreases it is called as _______.
Options
reduction
corrosion
oxidation
decomposition
Advertisements
Solution
When the positive charge on an ion increases or the negative charge on them decreases it is called as oxidation.
APPEARS IN
RELATED QUESTIONS
Corrosion can be prevented by using ……………. solution.
What is an oxidising agent?
Why does the colour of copper sulphate solution change when an iron nail is dipped in it?
Define corrosion.
What is meant by rust?
Write the chemical formula of rust.
Identify the component oxidised in the following reaction:
\[\ce{H2S + Cl2 -> S + 2HCl}\]
Give one example of an oxidation-reduction reaction which is also a combination reaction.
Explain the following in terms of gain or loss of oxygen with one example:
Oxidation
When copper powder is heated strongly in air, it forms copper oxide. Write a balanced chemical equation for this reaction. Name
- substance oxidised, and
- substance reduced.
Define the following in terms of gain or loss of hydrogen with one example:
Reduction
MULTIPLE CHOICE QUESTIONS
The process of adding oxygen to a substance is called
- oxidation.
- reduction.
- displacement.
- hydrogenation.
Identify the substances that are oxidised and the substances that are reduced in the following reaction.
\[\ce{CuO_{(s)} + H2_{(g)} -> Cu_{(s)} + H2O_{(l)}}\]
How would you change a metal like Cu into its ions?
The colours of aqueous solutions of CuSO4 and FeSO4 as observed in the laboratory are:
(A) pale green and light blue respectively
(B) light blue and dark green respectively
(C) dark blue and dark green respectively
(D) dark blue and pale green respectively
Identify from the reaction the reactants that undergo oxidation and reduction.
\[\ce{NiO + H2 -> Ni + H2O}\]
Compare hydrogen and halogens on the basis of:
reaction with oxygen
State, giving reason, whether the substances printed in bold letters have been oxidized or reduced.
Cl2 + H2S → 2HCl + S
State whether the following conversion is oxidation or reduction:
Cu2+ + 2 e-→ Cu
Write the equation in the ionic form
CuSO4(aq) + Fe(s)→ FeSO4(aq) + Cu(s)
Which of the following statements about hydrogen is incorrect?
For the reaction PbO + H2→ Pb + H2O, which of the following statements is wrong?
Name:
a substance that oxidizes concentrated HCl to chlorine.
Name:
a gas that is oxidizing as well as a reducing agent.
Complete and balance the following equation:
H2 + S → ___________
Complete and balance the following equation:
CuO +__________→ Cu +___________
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.
Explain the term redox reaction with an example involving the reaction of hydrogen sulphide with chlorine.
State what is oxidising agent. Give an example of oxidising agent in the gaseous, liquid, and solid form.
Balance the given chemical reaction as per the instructions below.
\[\ce{NaOH + H2SO4 -> Na2SO4 + H2O}\]
Oxidation means losing electrons then what is reduction?
Oxidising agents are also called as ______ because they remove electrons form other substances.
Identify the following reactions as oxidation or reduction
- Na → Na+ + e
- Fe3+ + 2 e- → Fe+
Find the oxidation number of the elements in the following compounds.
- C in CO2
- Mn in MnSO4
- N in HNO3
Oxidation is a process which involves ____________.
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 reducing agent in the following reactions
`"Fe"_2"O"_3 + 3"CO" -> 2"Fe" + 3"CO"_2`
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 temperature of the reaction mixture rises when aluminium (Al) is added.
Explain this observation giving suitable reason.
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.
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?
Oxidizing agents are otherwise called ______.
The tarnishing of metals is due to the formation of ______.
The tarnishing of metals is an example of ______ reaction.
Identify the following reactions as oxidation/reduction/redox reaction
CuO+H2 → Cu+H2O
What is rancidity?
Find the oxidation number of the element in the following compound.
N in NH3
State whether the given chemical reaction is a redox reaction or not. Justify your answer.
\[\ce{MnO_2 + 4HCl->MnCl_2 +2H_2O + Cl_2}\]
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
State the change in colour observed in following case mentioning the reason:
Copper powder is strongly heated in air.
Metals are good ______.
