11. Consider the following statements regarding the application of various elements and compounds:
- Nickel acts as a catalyst in the hydrogenation process used for the production of margarine.
- Galinstan, a liquid alloy consisting mainly of gallium, is used as a non-toxic alternative to mercury in thermometers.
- Germanium-doped silica is primarily utilized in manufacturing optical fibers for high-speed internet connectivity.
- Selenium is a common ingredient in anti-dandruff shampoos.
Which of the above statements is / are correct?
[A] Only 1 and 4
[B] 1, 2, 3 and 4
[C] Only 2 and 3
[D] 1, 2 and 3
Show Answer
Correct Answer: B [1, 2, 3 and 4]
Notes:
All four statements are correct: Nickel catalyzes hydrogenation in margarine production; galinstan replaces toxic mercury in thermometers; germanium-doped silica is preferred for optical fiber production due to superior properties; and selenium is included in anti-dandruff shampoos primarily as antifungal agent. Each element or compound listed has widespread industrial or commercial use as stated.
12. Consider the following elements:
- Bismuth
- Iodine
- Lithium
- Mercury
How many of the above are currently used in medicine?
[A] Only One
[B] Only Two
[C] Only Three
[D] All Four
Show Answer
Correct Answer: C [Only Three ]
Notes:
Bismuth (in antacids and ulcer medication), iodine (as antiseptic and in iodized salt), and lithium (used for bipolar disorder) are all commonly used in modern medicine. Mercury, though historically used in some medicines, is now avoided because of its toxicity. Thus, only three are correctly regarded as used in medicine today.
13. Who won the Gold Mercury Award 2025 for peace and stability?
[A] Tenzin Gyatso, the 14th Dalai Lama
[B] António Guterres
[C] Pope Francis
[D] None of the Above
Show Answer
Correct Answer: A [Tenzin Gyatso, the 14th Dalai Lama]
Notes:
Gold Mercury International awarded the Gold Mercury Award 2025 to Tenzin Gyatso, the 14th Dalai Lama. The award recognizes his efforts in promoting peace, compassion, and sustainability. The Dalai Lama urged world leaders to unite for global peace, cooperation, and environmental protection. He emphasized non-violence, wisdom, and environmental harmony as key values. Rooted in Buddhist philosophy, he advocates for all living beings and ecological balance. He remains a global symbol of non-violence and a strong voice for Tibetan rights and environmental conservation.
14. Consider the following pairs:
| Lead |
Element used in batteries |
| Mercury |
Element used in thermometers |
| Cadmium |
Element used in rechargeable batteries |
How many of the above pairs are correctly matched?
[A] Only one pair
[B] Only two pairs
[C] All three pairs
[D] None of the pairs
Show Answer
Correct Answer: C [All three pairs]
Notes:
- Lead: Indeed used in lead-acid batteries, which are commonly used in vehicles and backup power systems. Thus, this pair is correct.
- Mercury: Historically used in thermometers due to its high coefficient of expansion, allowing for accurate temperature readings. This pair is also correct.
- Cadmium: Used in nickel-cadmium (NiCd) rechargeable batteries, which are popular in portable electronics. This pair is correct as well.
Thus, all three pairs are correct.
15. In the context of astronomical phenomena, consider the following statements:
- A ‘planet parade’ occurs when multiple planets are visible in the night sky simultaneously.
- The last occurrence of a full ‘planet parade’ was in May-June 2024.
- Mercury is the only planet that requires a telescope to be seen from Earth.
- Planets do not twinkle, while stars do, due to atmospheric turbulence.
How many of the above statements are correct?
[A] Only one
[B] Only two
[C] Only three
[D] All four
Show Answer
Correct Answer: B [Only two]
Notes:
- A ‘planet parade’ occurs when multiple planets are visible in the night sky simultaneously: This is correct; it describes a common astronomical phenomenon.
- The last occurrence of a full ‘planet parade’ was in May-June 2024: This is incorrect; the last full parade was actually earlier.
- Mercury is the only planet that requires a telescope to be seen from Earth: This is incorrect; several planets can be seen without a telescope.
- Planets do not twinkle, while stars do, due to atmospheric turbulence: This is correct; planets maintain a steady brightness compared to stars.
Thus, two statements are correct.
16. Which of the following is / are correctly matched pairs?
- Agreement on Fisheries Subsidies – WTO agreement to regulate fisheries subsidies
- Rotterdam Convention – Treaty on reducing carbon emissions
- Cartagena Protocol – Biosafety agreement for managing GMOs
- Minamata Convention – Treaty addressing mercury pollution
Select the correct option from the codes given below:
[A] Only 1, 2 & 3
[B] Only 1, 3 & 4
[C] Only 2, 3 & 4
[D] 1, 2, 3 & 4
Show Answer
Correct Answer: B [Only 1, 3 & 4]
Notes:
The Rotterdam Convention deals with the trade of hazardous chemicals and is not about reducing carbon emissions. The Agreement on Fisheries Subsidies, Cartagena Protocol, and Minamata Convention are correctly matched with their purposes. The Rotterdam Convention specifically aims to regulate the trade of hazardous chemicals to ensure safety and informed consent among participating countries. Thus, options 1, 3, and 4 are correctly matched, whereas option 2 is incorrect.
17. Consider the following pairs regarding colours used in Holi and their corresponding chemical ingredients:
- Black – Lead oxide
- Green – Copper sulphate
- Silver – Aluminium bromide
- Red – Mercury sulphate
Which of the pairs given above are correctly matched?
[A] Only 1 and 4
[B] Only 2 and 3
[C] Only 1, 2 and 4
[D] 1, 2, 3 and 4
Show Answer
Correct Answer: D [1, 2, 3 and 4]
Notes:
All four pairs are correctly matched as per the composition of chemical-based Holi colours: Black colour uses lead oxide, green involves copper sulphate and malachite green, silver comes from aluminium bromide, and red is derived from mercury sulphate. These substances are often used in synthetic Holi colours, raising health concerns due to their toxicity.
18. Consider the following space missions:
- GRACE-FO – will explore Mercury’ atmosphere.
- DAVINCI+ will analyse Venus’s atmosphere.
- TRIDENT will explore Jupiter’s moon, Triton.
- PUNCH will study Solar winds from Sun’s outer corona.
Which of the statements given above is/are correct?
[A] Only 1 & 2
[B] Only 2 & 4
[C] Only 2 & 3
[D] Only 1 & 3
Show Answer
Correct Answer: B [Only 2 & 4]
Notes:
The GRACE-FO mission, a collaboration between NASA and the German Research Centre for Geosciences, follows the original GRACE mission (2002-2017) to study Earth’s gravity and climate. DAVINCI+ (Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging Plus) will analyze Venus’s atmosphere to explore its formation and potential ocean history. TRIDENT aims to investigate Neptune’s moon Triton to understand habitable world development in the Solar System. PUNCH (Polarimeter to Unify the Corona and Heliosphere) focuses on the transition of particles from the Sun’s corona to the solar wind.
19. Consider the following pairs:
- Arsenic — Black foot disease
- Lead — Intellectual Disability
- Chromium — Kidney Damage
- Mercury — Minamata Disease
- Cadmium — Blue baby Syndrome
Which of the above is/are not matched correctly?
[A] Only 1 and 5
[B] 3 and 5
[C] Only 5
[D] Only 1
Show Answer
Correct Answer: C [Only 5]
Notes:
Arsenic exposure leads to Black foot disease; lead causes intellectual disability; chromium damages both liver and kidneys; mercury leads to Minamata disease; however, cadmium causes Itai-Itai disease, not Blue baby syndrome. Blue baby syndrome is caused by nitrate-contaminated water. Hence, only pair 5 is out of place among the options given.
20. The mercury and sodium street lamps light up because of :
[A] Atomic emission
[B] Atomic absorption
[C] Electron emission
[D] Electron absorption
Show Answer
Correct Answer: A [Atomic emission]
Notes:
The light in sodium vapour lamp and mercury vapour lamp is, because of electron emission. In case of Sodium Lamps, filaments of the lamp sputter fast moving electrons, which hit the sodium atoms (vapour) causing the valence electrons of the sodium atoms to excite to higher energy levels and the electrons thus excited relax by emitting the characteristic monochromatic bright yellow light. The mechanism in mercury vapour lamp is more involved and sequential. The sputtered electrons from the filaments, after having been accelerated by high voltage, hit the mercury atoms. Here also, the excited electrons of mercury atoms relax by emitting characteristic but ultraviolet light.
