1. Consider the following statements:
- The flash point of a liquid hydrocarbon is the minimum temperature at which the liquid ignites without the presence of external ignition source
- The kindling point of a substance is the lowest temperature at which it ignites in presence of an external ignition source
Which of the above statements is/are correct?
[A] 1 Only
[B] 2 Only
[C] Both 1 & 2
[D] Neither 1 nor 2
Show Answer
Correct Answer: D [Neither 1 nor 2]
Notes:
Both are incorrect statements
First statement is incorrect because the flash point of a liquid hydrocarbon is the minimum temperature at which the liquid ignites in presence of ignition source. Second statement is also incorrect because the kindling point of a substance is the lowest temperature at which it ignites without an external ignition source.
2. Consider the following statements regarding Lignite coal:
- Lignite has higher moisture content in comparison to Bituminous coal
- Lignite is softer in comparison to Bituminous coal
- In India, Lignite is found in Tamil Nadu, Gujarat, as well as Rajasthan
Which of the above statements is / are correct?
[A] Only 1 and 2
[B] 1, 2 and 3
[C] Only 1
[D] Only 1 and 3
Show Answer
Correct Answer: B [1, 2 and 3]
Notes:
All the statements are correct. Lignite is the softest coal with the highest moisture content, making it less efficient than Bituminous coal. It is primarily used for power generation. In India, significant Lignite reserves are located in Tamil Nadu (Neyveli), Gujarat, and Rajasthan, accounting for its strategic importance in the energy sector.
3. Which of the following is / are applications of Guar Gum?
- Treating irritable bowel syndrome (IBS)
- Shale gas extraction
- Biofuel production
- Explosive industry
Select the correct option from the codes given below:
[A] 2, 3 and 4 only
[B] 2 and 3 only
[C] 1, 2 and 4 only
[D] 1, 2, 3 and 4
Show Answer
Correct Answer: C [1, 2 and 4 only]
Notes:
Guar Gum is widely used in treating IBS, shale gas extraction, and the explosive industry, due to its gelling, thickening, and water-blocking properties. However, it is not a typical component in biofuel production, as it lacks the chemical efficiency required for that process. Thus, statements 1, 2, and 4 only are correct.
4. Consider the following:
- Mica
- Graphite
- Sulphur
- Human body
Which among the above is / are electrical conductors?
[A] Only 1, 2 and 4
[B] Only 2 and 4
[C] Only 2, 3 and 4
[D] Only 2
Show Answer
Correct Answer: B [Only 2 and 4]
Notes:
Graphite conducts electricity due to its delocalized electrons, and the human body conducts electricity mainly because of ions in body fluids. Mica and sulphur are electrical insulators as they do not allow free flow of electrons.
5. Consider the following statements:
- The magnesium deficiency of soil can be cured by using Epsom Salt.
- Zinc is used to coat iron sheets to prevent them from rusting.
- Most ink erasers contain oxalic acid.
- In jet planes, a concentrated solution of hydrogen peroxide is used as a ready source of oxygen for burning the fuel.
Which of the above statements is/are correct?
[A] Only 1, 2 and 3
[B] Only 2, 3 and 4
[C] Only 1, 3 and 4
[D] 1, 2, 3 and 4
Show Answer
Correct Answer: D [1, 2, 3 and 4]
Notes:
Epsom salt (magnesium sulfate) corrects soil magnesium deficiency. Zinc is used to prevent rusting of iron via galvanization. Most ink erasers use oxalic acid as a bleaching agent. In jet and rocket propulsion, concentrated hydrogen peroxide decomposes catalytically to provide oxygen for combustion. Thus, all four statements are factually accurate.
6. Consider the following statements:
- Wheat has the largest content of DNA among all the food crops.
- India has contributed to the development of the draft sequence of the bread wheat genome.
- Decoding the genome sequence of wheat can help in developing climate-smart wheat.
Which of the above statements is / are correct?
[A] Only 1 and 2
[B] Only 2 and 3
[C] Only 1 and 3
[D] 1, 2 and 3
Show Answer
Correct Answer: D [1, 2 and 3]
Notes:
Wheat has one of the largest and most complex genomes among food crops, with bread wheat’s genome about six times that of humans. Indian scientists helped sequence this genome in collaboration with the International Wheat Genome Sequencing Consortium. Decoding the wheat genome enables targeted breeding for higher yields, climate resilience, and improved disease resistance.
7. Consider the following statements about Carbon nanotubes:
- Carbon nanotubes are good conductors of electricity and heat.
- They are much longer tubes with small diameters.
- They are used as adsorbent in removal of various inorganic and organic pollutants from polluted water.
Which of the above statements is/are correct?
[A] Only 1 and 2
[B] Only 2 and 3
[C] Only 1 and 3
[D] 1, 2 and 3
Show Answer
Correct Answer: C [Only 1 and 3]
Notes:
Statement 1 is correct as carbon nanotubes exhibit excellent electrical and thermal conductivity. Statement 3 is also correct because they are commonly used as adsorbents for pollutant removal in water treatment. Statement 2 is incorrect since carbon nanotubes are hollow structures with both small length and small diameter, rather than being much longer tubes.
8. Pure distilled water (H2O):
- does not conduct electricity
- boils at a higher temperature when table salt is added to it
- freezes at a lower temperature when table salt is added to it
- good for health
Choose the correct option from the codes given below:
[A] Only 1, 2 & 3
[B] Only 2, 3 & 4
[C] Only 2 & 3
[D] 1, 2, 3 & 4
Show Answer
Correct Answer: C [ Only 2 & 3]
Notes:
- Does not conduct electricity: This is an incorrect statement. Pure water is a poor conductor.
- Boils at a higher temperature when table salt is added to it: This is a correct statement. As soon as any of the salt dissolves in the water, the boiling point of the water will begin to rise — by about one half degree Celsius for every 58 grams of salt dissolved per kilogram of water. In fact, any non-volatile soluble substance will raise the boiling point of water. That is why antifreeze (ethylene glycol) provides boiling protection in winter as it simultaneously provides freezing protection in the summer.
- Freezes at a lower temperature when table salt is added to it: This is a correct statement. When the temperature of salt water is lowered, the molecules within in will lose energy and hence come closer together to try to form the hydrogen bonding required for ice. However, as impurities (salt) are in the way, they need to lose more energy so as to create the necessary bonding. Hence the lower freezing point.
- Good for health: This is not a correct statement. Pure water has no mineral and thus not good for health.
9. On the cellular level, the most important hazard due the use of persistent chemical DDT is that:
[A] It gets accumulated in the cytoplasm and hinders in metabolism
[B] It dissolves in the cell membrane and makes the cells to leak
[C] It binds with the cell membrane and makes it impermeable
[D] It changes the pattern of chemical bonds in the Chromosomes
Show Answer
Correct Answer: B [ It dissolves in the cell membrane and makes the cells to leak]
Notes:
The plasma membrane is made up mostly of lipids (fats). Remember that DDT is fat soluble, and so it will dissolve easily into the plasma membrane. In order to get into the plasma membrane, the DDT must open up the membrane slightly to make room for itself. DDT, unfortunately, opens up the membrane a little too much and causes the cell to leak. On the other hand, DDT is soluble in lipids (fats). This means that once an animal ingests a little DDT, it will mix in with its fat. And as we all know, all organisms (including human beings) have a certain amount of residual fat in their bodies. Once DDT gets in there, it tends to stay.
10. Which among the following is / are components of the Producer Gas?
- Carbon Monoxide (CO)
- Hydrogen (H2)
- Methane (CH4)
Select the correct option from the codes given below:
[A] Only 1 & 2
[B] Only 2 & 3
[C] Only 1 & 3
[D] 1, 2 & 3
Show Answer
Correct Answer: D [ 1, 2 & 3]
Notes:
Producer gas is created out of the biomass gasification i.e. incomplete combustion of biomass resulting in production of combustible gases consisting of Carbon Monoxide (CO), Hydrogen (H2) and traces of Methane (CH4). Producer gas can be used to run internal combustion engines (both compression and spark ignition) in vehicles; as a substitute for furnace oil in direct heat applications; produce methanol in an economically viable way.
