Tag: chemistry

Questions Related to chemistry

Primary, secondary and tertiary amines may be separated by using:

distinction between pairs of amines organic compounds containing nitrogen organic compounds with functional group containing nitrogen chemistry

  1. iodoform

  2. diethyloxalate

  3. benzenesulphonyl chloride

  4. acetyl chloride

Show answer
Correct Option: C
Explanation:

The amine is treated with benzenesulphonyl chloride  and shaken with alkali solution when the three amine because in different way$.$

Primary amine from alkyl benzesulphoramide which dissolve in alkali to from sodium potassium salt of mono alkyl benzene sulphoramide$.$ Secondary amine from dialkali benzene$,$ in soluble in alkali solution and tertiary amines do not react with benzene sulphonyl chloride at all$.$

Which of the following is not a property of diazonium salts?

distinction between pairs of amines organic compounds containing nitrogen organic compounds with functional group containing nitrogen chemistry

  1. Diazonium salts are colourless crystalline solids.

  2. Being ionic in nature they are soluble in water.

  3. Most of these salts explode when dried.

  4. The aqueous solutions of these salts are poor conductors of electricity.

Show answer
Correct Option: D
Explanation:

Salt solution such as sodium chloride ($NaCl$) conducts an electric current because it has ions in it that have the freedom to move about in solution. These ions are produced when sodium chloride dissolves in pure water to produce sodium ($Na^+$) and chloride ions ($Cl^–$).

Diazonium salts ($ArN _2^+X$) aqueous solutions are neutral to litmus and conduct electricity due to the presence of ions.
In an aqueous solution (that is, dissolved in water), the ions and electrons are much more mobile, thereby allowing electricity to flow through the solution.

Teflon and Neoprene are the example of:

copolymerisation types of polymerisation reactions polymer polymers chemistry

  1. copolymer

  2. monopolymer

  3. homopolymer

  4. condensation polymer.

Show answer
Correct Option: B,C
Explanation:

Teflon is homopolymer of monomeric units of tetra-fluoro-ethene

$CF _2=CF _2$
Neoprene is homopolymer of monomeric units of chloroprene [ $2-chloro-1,3-butadiene$].
so these are homopolymer and monomers, correct option is [B,C].

Which of the following sets contain only addition homopolymers?

copolymerisation types of polymerisation reactions polymer polymers chemistry

  1. Polythene, Natural rubber, Cellulose

  2. Nylon, Polyester, Melamine resin

  3. Teflon, Bakelite, Orlon

  4. Neoprene, PVC, Polythene

Show answer
Correct Option: A,D
Explanation:

On the basis of mode of polymerization, polymers can be classified into two types:-

[1] Addition polymer
[2] Condensation polymer
Addition polymers are formed by the repeated addition of monomer molecules possessing double or triple bonds. However, the addition polymers formed by the polymerization of a single monomeric species are known as homopolymers.
Example= Polythene: Made from the polymerization of ethene
Natural rubber: Made from the polymerization of cis-1,4-polyisoprene
Cellulose: Made from the polymerization of $\beta$ D- glucose
Neoprene: Made from the polymerization of chloroprene
PVC: Made from the polymerization of vinyl chloride

On complete hydrogenation, natural rubber produces:

copolymerisation types of polymerisation reactions polymer polymers chemistry

  1. ethylene-propylene copolymer

  2. vulcanized rubber

  3. polypropylene

  4. polybutylene

Show answer
Correct Option: A
Explanation:

Natural rubber forms due to polymerisation of isoprene and on hydrogenation provide a polymer of the ethylene-propylene copolymer.


Hence, option A is correct.

Polymerisation in which two or more chemically different monomers take part is called 

copolymerisation types of polymerisation reactions polymer polymers chemistry

  1. addition polymerisation

  2. copolymerisation

  3. chain polymerisation

  4. homopolymerisation

Show answer
Correct Option: B
Explanation:

Addition polymerisation - In this type of polymerisation, the molecules of the same monomer or different monomers add together on a large scale to form a polymer.
Copolymerisation - Copolymerisation is a polymerisation reaction in which a mixture of more than one monomeric species is allowed to polymerise to form a copolymer.
Chain polymerisation - Chain polymerisation or chain growth polymerisation is a polymerisation technique, where unsaturated monomer molecules add on to the active site on a growing polymerisation one at a time.
Homopolymerisation - Homopolymerisation is the polymerisation of a single type of monomer to form a homopolymer.

Buna-S is a copolymer of:

copolymerisation types of polymerisation reactions polymer polymers chemistry

  1. styrene and $1,:3$ - butadiene

  2. styrene and ethylene

  3. $1,:3$ - butadiene and ethylene

  4. $1,: 3$ - butadiene and acrylonitrile

Show answer
Correct Option: A
Explanation:

Buna-S is formed from styrene and $1,:3$ - butadiene.
The reaction is shown below:
$nCH _2=CH-CH=CH _2 + nC _6H _5CH=CH _2 \rightarrow -(CH _2-CH=CH-CH _2-CH _2-CH(C _6H _5)) _n-$

Which one of the following is an example of co-polymer ?

copolymerisation types of polymerisation reactions polymer polymers chemistry

  1. Buna - S

  2. Teflon

  3. PVC

  4. Polypropylrnr

Show answer
Correct Option: A
Explanation:

Copolymer is a polymer made of two or more than two different monomers.

Buna-S is made of $1,3-$butadiene and styrene monomer.
But others are made of single polymer only.
Teflon $\longrightarrow$ Tetrafluorocarbon.
PVC $\longrightarrow$ Vinyl Chloride.
Polypropylene $\longrightarrow$ Propylene.

Which of the following is not addition copolymer?

copolymerisation types of polymerisation reactions polymer polymers chemistry

  1. Saran

  2. Vinyon

  3. SBR

  4. PVC

Show answer
Correct Option: B

Which one is not a synthetic rubber?

copolymerisation types of polymerisation reactions polymer polymers chemistry

  1. Buna -S

  2. Homopolymers of 1, 3-butadiene derivative

  3. PVC

  4. Copolymer of 1, 3-butadiene

Show answer
Correct Option: B