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प्रश्न
Give scientific reason.
It is reccommended to use air tight container for storing oil for long time.
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उत्तर
- When edible oil is left aside for long time, it undergoes air oxidation.
- Due to this, the taste and smell of oil changes and it becomes rancid. If food is cooked in this oil, its taste also changes.
- Thus, the oil will become unfit for consumption.
- The process of oxidation reaction of oil can be slowed down by storing it in air tight container.
Hence, it is recommended to use air tight container for storing oil for long time.
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संबंधित प्रश्न
The chemical formula for rust is.............. .
Why does the colour of copper sulphate solution change when an iron nail is dipped in it?
Identify the substances that are oxidised and the substances that are reduced in the following reaction.
\[\ce{4Na(s) + O2(g) -> 2Na2O(s)}\]
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?
What are anti-oxidants?
Identify in the following reaction (a) the substance oxidised, and (b) the substance reduced:
\[\ce{ZnO + C -> Zn + CO}\]
In the reaction represented by the equation:
\[\ce{MnO2 + 4HCl -> MnCl2 + 2H2O + Cl2}\]
- name the substance oxidised.
- name the oxidising agent.
- name the substance reduced.
- name the reducing agent.
Is oxidation an exothermic or an endothermic reaction?
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:
Oxidation
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 context of redox reactions, the removal of hydrogen from a substance is known as ______.
In order to prevent the spoilage of potato chips, they are packed in plastic bags in an atmosphere of ______.
The process of respiration is ______.
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.
MULTIPLE CHOICE QUESTIONS
The process of adding oxygen to a substance is called
- oxidation.
- reduction.
- displacement.
- hydrogenation.
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
Compare hydrogen with alkali metals on the basis of:
Oxide formation
In what respect does hydrogen differ from:
alkali metals
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.
H2S + Cl2→ 2HCl + S
State whether the following conversion is oxidation or reduction:
Cu2+ + 2 e-→ Cu
State whether the following conversion is oxidation or reduction:
2Cl- - e-→ Cl2
In the following reaction: A+ + B → A + B+. Write half-reactions for this reaction and name:
- oxidizing agent
- substance oxidized
- reducing agent
Divide the above equation into oxidation and reduction half-reactions.
Which of the following statements about hydrogen is incorrect?
For the reaction PbO + H2→ Pb + H2O, which of the following statements is wrong?
Name:
an oxidizing agent that does not contain oxygen.
Explain the term oxidation 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.
Write chemical formula for rust.
Rusting of iron involves a chemical reaction which is a combination of:
The process of reduction involves ____________.
\[\ce{MnO2 + 4HCl -> + 2H2O + Cl2}\]
Identify the substance oxidized in the above equation.
Select the oxidising agent for the following reaction:
\[\ce{H2S + I2 -> 2HI + S}\]
Identify the oxidising agent (oxidant) in the following reactions
`2"Mg" + "O"_2 -> 2"MgO"`
Which among the following are physical or chemical change?
Burning of Liquefied Petroleum Gas (LPG)
Which among the following are physical or chemical change?
Sublimation of solid ammonium chloride
During the reaction of some metals with dilute hydrochloric acid, following observations are made.
Silver metal does not show any change
Explain this observation giving suitable reason.
On adding a drop of barium chloride solution to an aqueous solution of sodium sulphite, white precipitate is obtained :
- Write a balanced chemical equation for the reaction involved.
- What other name can be given to this precipitation reaction?
- On adding dilute hydrochloric acid to the reaction mixture, white precipitate disappears. Why?
The tendency of atoms to have eight electrons in the outer shell is known as ______.
Choose the odd one out and write the reason:
Identify the following reactions as oxidation/reduction/redox reaction
2Mg +O2 → 2MgO
What are reducing agents? Give examples.
Find the oxidation number of the element in the following compound.
A1 in AlCl3
In the redox reaction:
MnO2 + 4HCl → MnCl2 + 2H2O + Cl2
The metallic oxide which can be reduced by using common reducing agents is ______.
