Free Chemical Process Principles MCQs with Answers

• A. Boiling water
• B. Helium cooled
• C. Molten sodium cooled
• D. Pressurised water

Explanation: In a boiling-water reactor, water boils inside the reactor vessel and the generated steam goes directly to the turbine, so a separate…

• A. β-rays
• B. α-rays
• C. γ-rays
• D. X-rays

Explanation: Alpha particles are the least penetrating listed because they are relatively heavy and carry a +2 charge, causing intense ionisation over…

• A. Good absorber of neutrons
• B. Solid substance
• C. Poor absorber of neutrons
• D. None of these

Explanation: A moderator must slow neutrons efficiently while absorbing as few as possible, so that enough neutrons remain available to sustain the…

• A. Neutrons
• B. Protons
• C. Electrons and three protons
• D. Electrons

Explanation: Isotopes of the same element have the same number of protons and, in neutral atoms, electrons.

• A. Plutonium
• B. Enriched uranium
• C. Natural uranium
• D. Thorium

Explanation: A BWR generally uses low-enriched uranium fuel, usually uranium dioxide enriched in U-235.

• A. Graphite
• B. Heavy water
• C. No
• D. Beryllium

Explanation: Fast breeder reactors deliberately avoid a moderator so that fission neutrons remain fast.

• A. 1
• B. 9 x 10^21
• C. 3 x 10^11
• D. 2200

Explanation: A neutron with kinetic energy near 0.025 eV is a thermal neutron and travels at about 2,200 m/s at room temperature.

• A. Does not require a moderator
• B. Uses natural uranium as fuel
• C. Both A. and B.
• D. Neither A. nor B.

Explanation: A fast breeder reactor does not use a moderator, because moderation would slow the neutrons and reduce fast-neutron breeding.

• A. Pitchblende
• B. Monazite sand
• C. Cassiterite
• D. Chalcopyrite

Explanation: Pitchblende, also called uraninite, is the principal ore of uranium and contains uranium oxides.

• A. A + Z
• B. A
• C. A - Z
• D. Z

Explanation: The mass number A represents protons plus neutrons, whereas the atomic number Z represents protons.

• A. Radioactive
• B. All A., B. and C.
• C. Chemical
• D. Physical

Explanation: Hydrogen and deuterium have nearly identical chemical behavior because both have one electron, but their different masses produce…

• A. Both B. and C.
• B. Uranium-233
• C. Plutonium-239
• D. Uranium-235

Explanation: Uranium-233 is produced by neutron irradiation of thorium, while plutonium-239 is produced from uranium-238 in reactors, so both are…

• A. Helium
• B. Hydrogen
• C. Deuterium
• D. None of these

Explanation: A neutron has a mass of about 1 atomic mass unit, nearly equal to the mass of a hydrogen atom.

• A. Isotopes
• B. Isobars
• C. Isotones
• D. Isostere

Explanation: Isotones have the same number of neutrons but different numbers of protons and hence different mass numbers.

• A. 0.015
• B. 7.54
• C. 0.71
• D. 32.97

Explanation: Natural hydrogen contains about 0.015% deuterium, and heavy water is formed from this deuterium isotope.

• A. Has a low absorption cross-section
• B. Absorbs neutrons
• C. Has a low scattering cross-section
• D. Does not absorb neutrons

Explanation: Ordinary water contains hydrogen-1, which has a comparatively high neutron-absorption cross-section and captures neutrons that could…

• A. Madam Curie
• B. Roentgen
• C. Becquerel
• D. J.J. Thomson

Explanation: Henri Becquerel discovered spontaneous radioactivity in 1896 while investigating uranium salts.

• A. 1
• B. 2
• C. 3
• D. 7

Explanation: Thermal reactors commonly use uranium enriched to about 3% U-235, with the remainder primarily U-238.

• A. Progressively decreases
• B. Progressively increases
• C. Remains constant throughout
• D. May increase or decrease depending on the material

Explanation: Radioactive disintegration follows first-order decay, so the activity decreases continuously as fewer undecayed nuclei remain.

• A. Radioactive decay
• B. Nuclear fusion
• C. Thermionic emission
• D. Combustion

Explanation: Fission splits a heavy nucleus into smaller nuclei, whereas fusion combines light nuclei into a heavier one.