HDPE

Q. The ability of a substance to assume two or more crystalline structures is called

1. Isomerism
2. Polymorphism
3. Isomorphism
4. Amorphism

Q.

1kg of Ethylene undergo polymerisation completely, then the weight of polyethylene obtained is _______________gm.

1. 10³

2. 10¹⁰

3. 10¹⁰

4. 10⁵

Q. High density polyethylene(HDPE) can be prepared from ethylene by

1. Ziegler-Natta process
2. Heating with peroxides
3. Condensing in sealed tubes
4. Condensing with styrenes

Q.

Which of the following polymers soften on heating and harden on cooling? What are the polymers with this property collectively called? What are the structural similarities between such polymers?

Bakelite, urea-formaldehyde resin, polythene, polyvinyls, polystyrene.

Q. Identify (X):

1. $F_{2}C=C{F}_2$
2. $ClFC=CFCl$
3. $F_{2}C=CFCl$
4. $F_{2}C=CC{l}_2$

Q. Which of the following possesses highest melting point?

1. p-dichlorobenzene
2. m-dichlorobenzene
3. Chlorobenzene
4. o-dichlorobenzene

Q. What do you know about PVC?

Q. Select the properties of HDPE.

1. High density
2. High tensile strength
3. Low branching
4. Crosslinking

Q. LOW DENSITY POLYTHENE is a highly branched structure (cross linked polymer) or having some branches (branched chain polymer) ?

Q.

Which of the following polymers soften on heating and harden on cooling? What are the polymers with this property collectively called? What are the structural similarities between such polymers?

Bakelite, urea-formaldehyde resin, polythene, polyvinyls, polystyrene.

Q.

Zeigler-Natta catalyst is used in the preparation of:

1. High-density polythene

2. Low-density polythene

3. PVC

4. Dacron

Q. Consider the Assertion and Reason given below:
Assertion (A): Ethene polymerized in the presence of Ziegler Natta catalyst at high temperature and pressure is used to make buckets and dustbins.
Reason (R): High density polymers are closely packed and are chemically inert.
Choose the correct answer from the following:

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1. (A) and (R) both are wrong
2. Both (A) and (R) are correct and (R) is the correct explanation of (A)
3. Both (A) and (R) are correct but (R) is not the correct explanation of (A)
4. (A) is correct but (R) is wrong

Q. High density polyethylene (HDPE) can be prepared from ethylene by:

1. Ziegler-Natta process.
2. Heating with peroxides.
3. Condensing in sealed tubes.
4. Condensing with styrene.

Q. In the manufacture of polythene by the Ziegler process using ethylene, the temperature for proper polymerisation required is:

1. Below ${10}^{o}C$
2. ${10}^o$ to ${50}^{o}C$
3. ${50}^o$ to ${80}^{o}C$
4. ${80}^o$ to ${140}^{o}C$

Q. What is the code number on plastic bottle HDPE?

Q. Which of the following is correct statement? (1) Low density polyethylene is obtained under high pressure and room temperature (2) High density polyethylene has highly branched structure (3) High density polyethylene is obtained at atmospheric pressure (4) High density polyethylene is more flexible than low density polyethylene

Q.

Two thermoplastics?

Q. High density polythene is obtained by:

1. polymerization of ethene in a hydrocarbon solvent in the presence of Ziegler-Natta catalyst
2. polymerization of ethene under high pressure and temperature
3. free radical polymerization of ethene at low-temperature polymerization peroxide
4. polymerization of ethene in presence of carbon tetrachloride

Q. The basis on the mode of their formation, the polymers can be classified:

1. Both as addition and condensation polymers
2. As addition polymers only
3. As copolymers
4. As condensation polymers only

Q. In Ziegler-Natta polymerisation of ethylene, the active species are:

1. $C{H}_{2}C{H}_2$
2. $EtA$
3. $AlC{l}_3$
4. $T{i}^{3+}$

Q. What makes HDPE have higher density and strength as compared to LDPE?

1. It's because of a crystalline structure
2. It's because of the crosslinked molecular chains which enable better packing
3. It's because of linear chains which lead to better packing
4. It's because of branched chains which lead to better packing

Q. $B\stackrel{Y}{\leftarrow }2-butyne\stackrel{X}{\to }$ A. A and B are geometrically isomers. 'A' is more symmetrically than 'B'. 'B' has higher heat of hydrogenation than 'A'. Then 'X' and 'Y' are respectively:

1. $Li/LiqN{H}_3,H_2/$Lindlar's catalyst
2. $Li/Liq.N{H}_3,Na/Liq.N{H}_3$
3. $H_2/$ Lindlar's catalyst, $Na/Liq.N{H}_3$
4. $H_2/Pt,H_2/$ Lindlar's catalyst

Q. The catalyst used for the polymerization of olefins is:

1. Wilkinsons catalyst
2. Zeiglar - Natta catalyst
3. Zeise's salt complex
4. Pd catalyst

Q.

Why the Grignard reagent should be prepared under anhydrous conditions?

Q. Which of the following is not true about high density polythene?

1. Tough
2. Hard
3. Inert
4. Highly branched

Q. A direct iodination of benzene is not possible because :

1. Iodine is an oxidising agent
2. Resulting $C_6{H}_{5}I$ is reduced to $C_6{H}_6$ by $HI$
3. $HI$ is unstable
4. The ring gets deactivated

Q. Which polymer is matched with incorrect use?

1. High density polythene $-$ Buckets, pipes
2. Nylon 6, 6 $-$ Ropes, bristles for brushes
3. Orlon $-$ Synthetic wool, carpets
4. Glyptal $-$ Electrical switches, combs