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Multiple choice synthetic polyamides polymerisation chemistry

Nylon is a well-known polymer used in fabrics and motor tyres. Nylon$-6,6$ is made from hexamethylenetetramine (having six methyl groups) and :

  1. adipic acid, a six-carbon chain fatty acid

  2. sulphurous acid with six atoms of various elements

  3. sulphure hexafluoride with six fluorine atoms

  4. cobalt hexamine cation with six ammonia ligands
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Nylon is a generic name for a synthetic linear polymer with repeating amide groups $(−NH−CO−)$ which is used in the manufacture of textile fibres. Carothers produced Nylon-66 by the condensation reaction of adipic acid (a dicarboxylic acid with 6 carbon atoms) and hexamethylene-di-amine (a diamine with 6 carbon atoms) give the $[−NH−{(C{H} _{2})} _{6}−NH−CO{(C{H} _{2})} _{4}−CO−]$ repeating unit. Nylon revolutionised the textile industry and was the forerunner for many of today's modern, synthetic fabrics.
Multiple choice synthetic polyamides polymerisation chemistry

Which of the following polymers are used as fibre?

  1. Nylon

  2. Polytetrafluoroethane

  3. Terylene

  4. Buna-S
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Nylon is used as fiber because, it is very important substitute of silk, it's other properties is elasticity, strength and resistance for mildew.

So the correct option is [A].

Multiple choice synthetic polyamides polymerisation chemistry

Polymer which has amide linkage is:

  1. nylon-$6,6$

  2. terylene

  3. teflon

  4. bakelite
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Polyamides have the amide linkage.

Example- Nylon 6-6, Nylon 6
Nylon 6, 6 is used in making sheets, bristles for brushes and in the textile industry.

The correct option is [A].

Multiple choice synthetic polyamides polymerisation chemistry

The ratio between the $\pi -$ bonds in the monomers of N-vinylpyrolidone and perlon-L is:

  1. $2 : 1$
  2. $1 : 2$
  3. $3: 2$
  4. $2 : 3$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

N-vinylpyrrolidone has a double bond in the vinyl group and one in the carbonyl group (2 total). Perlon-L (Caprolactam) has one double bond in the carbonyl group. The ratio is 2:1.

Multiple choice synthetic polyamides polymerisation chemistry

Which of the following polymers does not have vinylic monomer units?

  1. Acrilan

  2. Nylon

  3. Polystyrene

  4. Neoprene
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
 Acrilan  $(-CH _2=CHCN-) _n$
 Polystyrene  $(-C _6H _5-CH _2=CH _2-) _n$
 Neoprene  $(-CH _2=CHCl-) _n$
 Nylon  $(Hexa methylene \,di amine + adipic\,acid) _n$

Only nylon does not have vinylic monomer units.

So the correct option is [B].

Multiple choice synthetic polyamides polymerisation chemistry

The polymer formed by the condensation of hexamethylenediamine and adipic acid is

  1. Teflon

  2. Bakelite

  3. Dacron

  4. Nylon-66
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The polymer formed by the condensation of hexamethylenediamine $\displaystyle (H _2N-(CH _2) _6-NH _2)$ and adipic acid $\displaystyle (HOOC-(CH _2) _4-COOH)$ is Nylon-66.
$\displaystyle H _2N-(CH _2) _6-NH _2+HOOC-(CH _2) _4-COOH  \xrightarrow {\Delta} H _3N^+-(CH _2) _6-NH _3^+O^-OC-(CH _2) _4-COO^-$


$\displaystyle nH _3N^+-(CH _2) _6-NH _3^+O^-OC-(CH _2) _4-COO^-\xrightarrow [-H _2O]{\Delta} \underset{\text{Nylon} 6,6}{[HN-(CH _2) _6-NH \underset {\displaystyle  \underset {\displaystyle \text {O }}{||} }{C}-(CH _2) _4- \underset {\displaystyle  \underset {\displaystyle \text {O }}{||} }{C}] _n}$

Multiple choice chemistry chemical kinetics introduction to chemical kinetics understanding chemical kinetics rate of chemical reaction

Fill up the following with suitable terms.

(i) Activation energy $=$ Threshold energy $-$ ____.

(ii) Half-life period of zero order reaction $=$ __.

(iii) Average rate of reaction $=$ _.

(iv) Instantaneous rate of reaction $=$ ___.

  1. Potential energy, $\dfrac {0.693}{k}, \dfrac {dx}{dt}, \dfrac {\triangle [A]}{\triangle t}$
  2. Energy of reactants, $\dfrac {1}{k}, \dfrac {\triangle [A]}{\triangle t}, \dfrac {dx}{dt}$
  3. Energy of reaction, $\dfrac {\log k}{t}, \dfrac {\triangle [A]}{\triangle t}, \dfrac {dx}{dt}$
  4. Average kinetic energy of reactants, $\dfrac {a}{2k}, \dfrac {\triangle [A]}{\triangle t}, \dfrac {dx}{dt}$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
a) Activation energy = Threshold energy$-$ the Average kinetic energy of molecules(by definition)

b) half-life of a zero order reaction = ${ t } _{ \frac { 1 }{ 2 }  } =\frac { a }{ 2k } $

c) Average rate of reaction = $\dfrac {\displaystyle \text{ Total change concentration reactants }}{ \displaystyle \text{Total time taken} }$  = $\dfrac { \triangle \left[ A \right]  }{ \triangle t }$

d) Instantaneous rate of reaction =$ \dfrac { \displaystyle \text {Instantaneous change in concentration} }{\displaystyle \text { Instantaneous  time} } $=$\dfrac { dx }{ dt } $                    
Multiple choice chemistry chemical kinetics introduction to chemical kinetics understanding chemical kinetics rate of chemical reaction

Chemical kinetics a branch of physical chemistry deals with:

  1. structure of molecules

  2. heat changes in a reaction

  3. physical changes in a reaction

  4. rate of reactions
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Chemical kinetics is branch of physical chemistry that is concerned with understanding the rates of chemical reactions.

Structures and physical changes are deal in solid state and while studying liquids.

Thermochemistry deals with energy changes in chemical reactions.


Multiple choice chemistry chemical kinetics introduction to chemical kinetics understanding chemical kinetics rate of chemical reaction

If reaction A and B are given with Same temperature and same concentration but rate of $A$ is double than $B$. Pre exponential factor is same for both the reaction then difference in activation energy $E _{A} - E _{B}$ is?

  1. $-RT\ ln2$
  2. $RT\ ln2$
  3. $2RT$
  4. $\dfrac {RT}{2}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

$\dfrac {r _{A}}{r _{B}} = \dfrac {A _{1}e^{\dfrac {-E _{A}}{RT}}}{A _{2}e^{\dfrac {-E _{B}}{RT}}}$
$\dfrac {2}{1} = \dfrac {e^{\dfrac {-E _{A}}{RT}}}{e^{\dfrac {-E _{B}}{RT}}}$
$ln2 = E _{B} - E _{A} / RT$
$E _{B} - E _{A} = RT\ ln2$
$E _{A} - E _{B} = -RT\ ln2$.

Multiple choice chemistry chemical kinetics introduction to chemical kinetics understanding chemical kinetics rate of chemical reaction

Which of the following theory is not related to the chemical kinetics?

  1. Collision theory

  2. Absolute theory

  3. Absolute reaction rate

  4. VSEPR theory
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Valence shell electron pair repulsion (VSEPR) theory is a model used in chemistry to predict the geometry of individual molecules from the number of electron pairs surrounding their central atoms.

It's not related to the chemical kinetics.