हिंदी

Give scientific reason. It is reccommended to use air tight container for storing oil for long time.

Advertisements
Advertisements

प्रश्न

Give scientific reason.

It is reccommended to use air tight container for storing oil for long time.

स्पष्ट कीजिए
टिप्पणी लिखिए
Advertisements

उत्तर

  1. When edible oil is left aside for long time, it undergoes air oxidation.
  2. 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.
  3. Thus, the oil will become unfit for consumption.
  4. 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.
shaalaa.com
  क्या इस प्रश्न या उत्तर में कोई त्रुटि है?
अध्याय 3: Chemical reactions and equations - Write scientific reasons [पृष्ठ २३]

APPEARS IN

एससीईआरटी महाराष्ट्र Science and Technology Part 1 [English] Standard 10 Maharashtra State Board
अध्याय 3 Chemical reactions and equations
Write scientific reasons | Q 2. | पृष्ठ २३
बालभारती Science and Technology Part 1 [English] Standard 10 Maharashtra State Board
अध्याय 3 Chemical reactions and equations
Exercise | Q 4. d. | पृष्ठ ४५

वीडियो ट्यूटोरियलVIEW ALL [2]

संबंधित प्रश्न

Why is photosynthesis considered an endothermic reaction?


Identify the component oxidised in the following reaction:

\[\ce{H2S + Cl2 -> S + 2HCl}\]


Give an example of an oxidation reaction.


Define the following in terms of gain or loss of hydrogen with one example:

Reduction


In the context of redox reactions, the removal of hydrogen from a substance is known as ______.


You are given the following chemical equation:

\[\ce{Mg_{(s)} + CuO_{(s)} -> MgO_{(s)} + Cu_{(s)}}\]

This equation represents:


Define an oxidation reaction.


Define redox reaction.


TRUE \ FALSE

Hydrogen is a good oxidizing agent.


 Explain the following in term Reduction of gain or loss of oxygen with two example.


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.
Fe + S → FeS


Identify from the following reaction the reactants that undergo oxidation and reduction.

\[\ce{2Ag2O → 4 Ag + O2 \uparrow}\]


Compare hydrogen with alkali metals on the basis of:

Oxide formation 


State, giving reason, whether the substances printed in bold letters have been oxidized or reduced.

PbO + CO → Pb + CO2


State, giving reason, whether the substances printed in bold letters have been oxidized or reduced.

Mg + 2HCl → MgCl2 + H2


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:

PbO2 + SO2→ PbSO4 


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)

 


Name:

a substance that will reduce aqueous Iron(III)ions to iron(II)ions.


 Complete and balance the following equation:

H2 + S → ___________


Complete and balance the following equation:

Zn +_________________→ZnCl2 + H2 


Distinguish between oxidation and reduction.

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 oxidation in term of addition and removal of oxygen/hydrogen with a suitable example. 


State what is oxidising agent. Give an example of oxidising agent in the gaseous, liquid, and solid form.


Select the correct answer from the symbol in the bracket.

The element, which like hydrogen is a strong reducing agent.


When the positive charge on an ion increases or the negative charge on them decreases it is called as _______.


Write chemical formula for rust.


Rusting of iron involves a chemical reaction which is a combination of:


\[\ce{MnO2 + 4HCl -> + 2H2O + Cl2}\]

Identify the substance oxidized in the above equation.


Select the oxidising agent for the following reaction:

\[\ce{H2S + I2 -> 2HI + S}\]


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 - 

`"H"_2"O" + "F"_2 -> "HF" + "HOF"`


Identify the oxidising agent (oxidant) in the following reactions

`"CuSO"_4 + "Zn" -> "Cu" + "ZnSO"_4`


Identify the oxidising agent (oxidant) in the following reactions.

`"CuO" + "H"_2 -> "Cu" + "H"_2"O"`


Which among the following are physical or chemical change?

 Evaporation of petrol


Which among the following are physical or chemical change?

Heating of an iron rod to red hot


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.


A silver article generally turns black when kept in the open for a few days. The article when rubbed with toothpaste again starts shining.

  1.  Why do silver articles turn black when kept in the open for a few days? Name the phenomenon involved.
  2. Name the black substance formed and give its chemical formula.

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.


The tarnishing of metals is due to the formation of ______.


The tarnishing of metals is an example of ______ reaction.


The sum of the oxidation number of all atoms in a compound is ______.


Identify the following reactions as oxidation/reduction/redox reaction

Zn + CuSO4 → Cu + ZnSO4


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.

A1 in AlCl3


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.

  1. Write the equation.
  2. What type of reaction is it?
  3. 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.

Answer the questions based on the equation below:

\[\ce{CH3 - CH2 - OH ->[{[O]}][K2Cr2O7/H2SO4] CH3 - COOH}\]

  1. What type of reaction is it?
  2. What is the role of the chemical written on the arrow?
  3. Give one example of one such type of chemical as in answer (b).

State the change in colour observed in following case mentioning the reason:

Copper powder is strongly heated in air.


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×