Tag: chemistry

Questions Related to chemistry

Teflon (tetrafluoroethylene) is a black material used in non-stick pans for frying chips and vegetables. The oil or butter does not stick at all. In the process of manufacture, one of the technical problems is:

chemistry polymer polymers of commercial importance some commercially important polymers condensation polymers

  1. to make teflon stick to the metal of the pan

  2. to make teflon that is non-sticky

  3. to make teflon

  4. to cut a round sheet of teflon that exactly fits

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Correct Option: A
Explanation:

Teflon even when melted do not flow instead it behaves as a gel due to absence of crystalline phase and high melting point so manufactures finds a bit difficulty to make teflon stick to metal of pan.

Which monomer is used in preparation of orlon?

chemistry polymer polymers of commercial importance some commercially important polymers condensation polymers

  1. $CF _2=CF _2$

  2. $CH _2=CH-CN$

  3. $CH _2=CH-Cl$

  4. $CH _2=CH-OH$

Show answer
Correct Option: B
Explanation:

Vinyl cyanide $ \displaystyle (CH _2=CH-CN)$ is the monomer that is used in preparation of orlon.

$ \displaystyle nCH _2=CH(CN)  \to [-CH _2-CH(CN)-] _n$.

Hence, the correct option is $B$.


Identify $X$ in the reaction.


$CHCl _3 \xrightarrow[HF]{SbF _3} CHF _2Cl \overset{1070\, K}{\rightarrow} (X)+2HCl$

chemistry polymer polymers of commercial importance some commercially important polymers condensation polymers

  1. $F _2C=CF _2$

  2. $ClFC=CFCl$

  3. $F _2C=CFCl$

  4. $F _2C=CCl _2$

Show answer
Correct Option: A
Explanation:

When chloroform is treated with antimony trifluoride and $HF$, 2 chlorine atoms are replaced with 2$ F$ atoms. 


When $\displaystyle CHF _2Cl $ is heated to 1070 K, terafluoroethylene (compound X) is obtained. 

$\displaystyle 2CHF _2Cl \xrightarrow {1070K} F _2C=CF _2 $

Which of the following fibres is a polyesters?

chemistry materials polymers of commercial importance some commercially important polymers condensation polymers

  1. Terylene

  2. Nylon-66

  3. Nylon-6

  4. Rayon

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Correct Option: A
Explanation:

Terylene fibres are made up of polyesters as they have repeating $-O-\underset { \parallel \ O }{ C } -$-group.

What substance is formed when $F _2C = CF _2$ is polymerized?

chemistry materials polymers of commercial importance some commercially important polymers condensation polymers

  1. Polyethylene

  2. Polyurathene

  3. PVC

  4. Teflon

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Correct Option: D

The mass of potassium dichromate crystals required to oxidise $ 750 cm^3  $ of 0.6 m mohr's salt solution is ( molar mass = 392 ) 

chemistry materials polymers of commercial importance some commercially important polymers condensation polymers

  1. 0.49g

  2. 0.45 g

  3. 22.05 g

  4. 2.2 g

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Correct Option: C

Which out of the following has smell similar to that of vinegar?

chemistry carbon and its compounds some important carbon compounds ethanol and ethanoic acid introduction to alcohols - ethanol

  1. Methanol

  2. Ethanol

  3. Ethanoic acid

  4. Formic acid

Show answer
Correct Option: C
Explanation:

Vinegar is a liquid having acetic acid and water as its mixture. So, ethanoic acid is the other name of acetic acid and this smell of vinegar is similar to ethanoic acid. 

Ethanol is:

chemistry carbon and its compounds some important carbon compounds ethanol and ethanoic acid introduction to alcohols - ethanol

  1. ionic compound

  2. noble gas

  3. polar covalent compound

  4. non-polar covalent compound

Show answer
Correct Option: C
Explanation:

Ethanol can be written as $CH _3-CH _2-OH$. The oxygen atom in the hydroxyl ($OH$) group is highly electronegative and hence attracts the electrons towards itself. Thus, ethanol is a polar compound with its electrons more towards the oxygen atom. Although ($C _2H _5$) group is non polar.

All the bonds in ethanol are covalent in nature. The bonds are formed by sharing of electrons between the atoms.
Thus, option $C$ is the correct answer.

Which of the following reagent reacts with ethanoic acid to liberate hydrogen gas?

chemistry carbon compounds some important carbon compounds ethanol and ethanoic acid introduction to alcohols - ethanol

  1. Na

  2. Zn

  3. Both A and B

  4. Cl

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Correct Option: C
Explanation:

Na or Zn reacts with ethanoic acid to liberate hydrogen gas.


$2CH _3COOH +2Na \rightarrow 2CH _3COONa + H _2$

Hence the correct option is C.

What is the action of the following reagents on ethanoic acid?

chemistry carbon compounds some important carbon compounds ethanol and ethanoic acid introduction to alcohols - ethanol

  1. $LiAl{H} _{4}/{H} _{3}{O}^{+}$

  2. $P{Cl} _{3}$, heat

  3. ${P} _{2}{O} _{5}$, heat

  4. None of the above

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Correct Option: A