160. Regarding the Petroleum and Natural Gas Regulatory Board:
1. It was India’s first regulatory body.
2. It seeks competitive gas markets.
3. Appeals go to the electricity appellate tribunal.
Which are correct?
[UPSC CSE Prelims — 2019]
(A) 1 and 2 only
(B) 2 and 3 only
(C) 1 and 3 only
(D) All three
Answer: (B) 2 and 3 only
Explanation: The board regulates specified activities in petroleum products and natural gas, supporting fair competition and consumer interests. It was not the first regulator created by India. Appeals are made to the relevant appellate tribunal under the statutory framework, so statements 2 and 3 are correct.
159. Which listed antibiotic is usually classed as narrow-spectrum?
[NEET Chemistry — 2019]
(A) Amoxicillin
(B) Chloramphenicol
(C) Penicillin G
(D) Ampicillin
Answer: (C) Penicillin G
Explanation: Penicillin G is mainly effective against susceptible Gram-positive organisms and is commonly classified as a narrow-spectrum antibiotic. Amoxicillin and ampicillin have extended antibacterial spectra, and chloramphenicol is broadly active. Actual clinical efficacy depends on organism susceptibility and resistance.
158. Match HDPE, polyacrylonitrile, novolac and nylon-6 with Ziegler–Natta catalyst, peroxide initiator, acid/base catalyst and high-temperature condensation respectively.
[JEE Main Online 10 Apr Evening Chemistry — 2019]
(A) HDPE-acid/base; PAN-condensation; novolac-peroxide; nylon-6-Ziegler–Natta
(B) HDPE-Ziegler–Natta; PAN-peroxide; novolac-acid/base; nylon-6-condensation
(C) HDPE-condensation; PAN-acid/base; novolac-peroxide; nylon-6-Ziegler–Natta
(D) HDPE-Ziegler–Natta; PAN-peroxide; novolac-condensation; nylon-6-acid/base
Answer: (B) HDPE-Ziegler–Natta; PAN-peroxide; novolac-acid/base; nylon-6-condensation
Explanation: High-density polyethylene can be made using coordination catalysts, while acrylonitrile commonly polymerises through radical initiation. Novolac phenolic resins form by catalysed condensation, and nylon-6 forms from caprolactam under suitable polymerisation conditions. The matching hinges on distinguishing polymer reaction types.
157. Which of the polymers listed is a condensation polymer?
[JEE Main Online 10 Apr Morning Chemistry — 2019]
(A) Neoprene
(B) Buna-S
(C) Nylon-6,6
(D) Teflon
Answer: (C) Nylon-6,6
Explanation: Nylon-6,6 has repeating amide linkages and forms by condensation between a diamine and a dicarboxylic acid. Buna-S, neoprene and Teflon are normally described as addition or chain-growth polymers. The presence of an amide backbone helps recognise nylon as a polyamide.
156. Which of the following is a thermosetting polymer?
[RPSC Senior Teacher Science — 01 Nov 2018]
(A) Terylene
(B) Polystyrene
(C) Bakelite
(D) Neoprene
Answer: (C) Bakelite
Explanation: Bakelite is a cross-linked phenol-formaldehyde resin. Once cured, its network cannot simply be melted and reshaped like many thermoplastic polymers. Terylene and polystyrene are thermoplastics, while neoprene is an elastomer used for its flexible properties.
155. Which polymer used in paints is synthesised using ethylene glycol and phthalic acid?
[RPSC Senior Teacher Science — 01 Nov 2018]
(A) Dacron
(B) Bakelite
(C) Polystyrene
(D) Glyptal
Answer: (D) Glyptal
Explanation: Glyptal is an alkyd or polyester resin obtained by condensation of ethylene glycol with phthalic acid. Its film-forming properties support use in paints and surface coatings. Dacron and Bakelite involve different monomer combinations.
154. What is the chemical nature of vinegar?
[WBCS Prelims — 2018]
(A) Sodium nitrate
(B) Dilute acetic acid
(C) Chloride of lime
(D) Calcium
Answer: (B) Dilute acetic acid
Explanation: Vinegar is a dilute aqueous solution of acetic acid, also called ethanoic acid, CH₃COOH. Its acidity gives vinegar its sour taste and helps preserve foods. It is produced commercially through biological oxidation of ethanol by acetic acid bacteria.
153. What does PVC stand for in the plastics industry?
[WBCS Prelims — 2018]
(A) Polyvinyl chloride
(B) Polyvinyl carbonate
(C) Phosphor vanadium chloride
(D) Phospho vinyl chloride
Answer: (A) Polyvinyl chloride
Explanation: PVC is polyvinyl chloride, a widely used synthetic thermoplastic formed from vinyl chloride monomers. It is chemically resistant and can be formulated as either rigid or flexible material. Familiar applications include pipes, cable insulation, flooring and protective coverings.
152. Adding a non-volatile solute to benzene at 30°C causes its vapour pressure to:
[RPSC Senior Teacher Science — 01 Nov 2018]
(A) Increase
(B) Decrease
(C) Remain unchanged
(D) Depend only upon the solute
Answer: (B) Decrease
Explanation: Adding a non-volatile solute reduces the mole fraction of benzene in the liquid phase. Under ideal-solution conditions, Raoult’s law predicts a proportional reduction in the solvent vapour pressure. Thus the solution has a lower vapour pressure than pure benzene.
151. Which of the following is a renewable energy source?
[CGPSC Civil Service Prelims — 2018]
(A) Coal
(B) Petroleum
(C) Biomass
(D) Kerosene
Answer: (C) Biomass
Explanation: Biomass comes from recently living material and may be replenished through sustainable growth and waste recovery. It can supply combustible solids, biogas and some liquid biofuels. Coal, petroleum and kerosene are fossil-derived, non-renewable sources over human timescales.
