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प्रश्न
It is recommended to use air tight containers for storing oil for a long time.
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उत्तर
When oil or ghee is left out for an extended period of time, it oxidises and becomes rancid due to air oxidation. Antioxidants are used to prevent rancidity in foods cooked in oil or ghee. The oxidation reaction of food can also be slowed by storing it in an air tight container.
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संबंधित प्रश्न
Corrosion can be prevented by using ……………. solution.
The chemical formula for rust is.............. .
Identify in the following reaction (a) the substance oxidised, and (b) the substance reduced:
\[\ce{ZnO + C -> Zn + CO}\]
When SO2 gas is passed through saturated solution of H2S, the following reaction occurs:
\[\ce{SO2 + 2H2S -> 2H2O + 3S}\]
In this reaction, which substance is oxidised and which one is reduced?
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.
Define the following in terms of gain or loss of hydrogen with one example:
Oxidation
Name the following:
The process in which oxygen is added or hydrogen is removed.
Electrolysis is a redox process. Explain.
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.
2Mg + O2 → 2MgO
Why zinc and aluminium are considered to have a unique nature. Give balanced equations to support your answer.
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.
H2S + Cl2→ 2HCl + S
In the following reaction: A+ + B → A + B+. Write half-reactions for this reaction and name:
- oxidizing agent
- substance oxidized
- reducing agent
Write the equation in the ionic form
CuSO4(aq) + Fe(s)→ FeSO4(aq) + Cu(s)
A metal oxide that is reduced by hydrogen is
Complete and balance the following equation:
Fe + H2O →___________+____________
State a reason why, when hydrogen is passed over heated copper oxide, the resultant product formed, differs in colour from the original reactant.
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.
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.
When the positive charge on an ion increases or the negative charge on them decreases it is called as _______.
Write chemical formula for rust.
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:
Identify the reducing agent in the following reactions
`2"H"_2 + "O"_2 -> 2"H"_2"O"`
Identify the oxidising agent (oxidant) in the following reactions
`2"Mg" + "O"_2 -> 2"MgO"`
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?
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?
Write a short note on oxidizing and reducing agents.
Mention some oxidation reactions that occur in daily life.
The formation of brown colour on the freshly unit surface of vegetables and fruits is because ______ of organic compounds present in them.
Oxidizing agents are otherwise called ______.
The sum of the oxidation number of all atoms in a compound is ______.
What are reducing agents? Give examples.
State whether the given chemical reaction is a redox reaction or not. Justify your answer.
\[\ce{MnO_2 + 4HCl->MnCl_2 +2H_2O + Cl_2}\]
