General Science Chemistry MCQs
Chemistry Objective (Multiple Choice) General Knowledge Questions & Answers for SSC-CGL, UPPSC, UPSC, NDA, CDS and UPSC Civil Services Prelims Examination
11. Which of the following is an anti-knocking compound that has been phased out in many countries so far?
[A] Lead tetrachloride
[B] Tetra Ethyl Lead
[C] Ethyl acetate
[D] None of the above
Show Answer
Correct Answer: B [Tetra Ethyl Lead ]
Notes:
Tetra Ethyl Lead (TEL) is one such component that is added to petrol to reduce its tendency to `ping’ under compression. TEL breaks down to lead at upper cylinder temperatures. Lead atoms spread around and combining with the free radicals and slowing down the reaction.
However, `Leaded’ petrol was a grave danger to the environment, as lead is a poison when it is absorbed into the body.
12. Highest percentage of nitrogen is found in which among the following fertilizers among the given options?
[A] Calcium ammonium nitrate
[B] Ammonium nitrate
[C] Calcium nitrate
[D] Urea
Show Answer
Correct Answer: D [Urea]
Notes:
The agricultural industry widely uses urea, a white crystalline solid containing 46 percent nitrogen as an animal feed additive and fertilizer. Urea has the highest nitrogen content of all solid fertilizers at 46% N.
13. Who among the following scientists had discovered Radium?
[A] Marie Sklodowska-Curie and Pierre Curie
[B] André-Louis Debierne
[C] Kasimir Fajans
[D] Oswald Helmuth Göhring
Show Answer
Correct Answer: A [Marie Sklodowska-Curie and Pierre Curie ]
Notes:
Radium is a chemical element with the symbol Ra and atomic number 88. Radium was discovered by Marie Sklodowska Curie, a Polish chemist, and Pierre Curie, a French chemist, in 1898.
14. Calcium Magnesium Silicate is commonly called as ________?
[A] Asbestos
[B] Borax
[C] Baking Soda
[D] Washing Soda
Show Answer
Correct Answer: A [Asbestos]
Notes:
CaMgO4Si is the chemical formula of calcium magnesium silicate . Calcium magnesium silicate is commonly known as Asbestos. Asbestos is a fibrous silicate mineral as the substance is formed by miniature crystal fibers, these crystal are loosely attached releasing dust of silicate crystal upon small touch.
15. Argon is the third most common gas in the Earth’s atmosphere, at 0.93%. This gas is generated due to decay of which among the following isotopes in the Earth’s crust ?
[A] K-40
[B] Ca-40
[C] Ca-48
[D] K-41
Show Answer
Correct Answer: A [ K-40]
Notes:
Potassium-40, which is a rare radioactive isotope of potassium has a very long half life. It undergoes all three types of beta decay (ß-, ß+ and electron capture). About 89% of the time 40K decays to calcium-40 (40Ca). However, 11% of the time it decays to argon-40 (40Ar).
16. Which among the following is produced when we pass chlorine into slaked lime?
[A] DDT
[B] Baking Powder
[C] Bleaching Powder
[D] Gypsum
Show Answer
Correct Answer: C [ Bleaching Powder]
Notes:
Bleaching powder is made by passing Cl2 into slaked lime. Though bleaching powder is often written as Ca(OCl)2 , it is really a mixture and not a compound.
17. Consider the following statements:
- The sulphur content in sour crude oil is higher in comparison to sweet crude oil
- Brent crude oil is a sour crude oil
- Most of Brent crude oil comes from North Sea
Which among the above statements is / are correct?
[A] Only 1 & 2
[B] Only 1 & 3
[C] Only 2 & 3
[D] 1, 2 & 3
Show Answer
Correct Answer: B [ Only 1 & 3]
Notes:
The oil which contains sulphur amount less than 0.5% is called Sweet Crude Oil. If the Sulphur content is more than 0.5%, it will be called Sour Crude Oil. The Brent crude oil is having around 0.37% Sulphur and that is why Brent Crude Oil is a Sweet crude Oil. Sweet Crude Oil is of High quality, low sulphur crude oil used for processing of gasoline. The more amount of Sulphur in sour crude makes it toxic, and production of Gasoline is more expensive in case of sour crude. The word “sweet” since a gently sweet taste and pleasing aroma due to the little level of Sulfur gives the oil with. The Brent Crude Oil is a sweet crude oil mainly produced in North Sea. It is largest of the several key classifications of crude oil comprising of Ekofisk, Brent Crude, Forties, Brent Sweet Light Crude and Oseberg. Its manufacturer also known as London Brent, Brent petroleum and Brent Blend.
18. Consider the following statements:
1.’sweet’ crude is more valuable in comparison to ‘sour’ crude
2.Mumbai High crude produced by ONGC is sweet crude
Which among the above statements is / are correct?
[A] Only 1
[B] Only 2
[C] Both 1 & 2
[D] Neither 1 nor 2
Show Answer
Correct Answer: C [ Both 1 & 2]
Notes:
Sulphur has to be removed during the refining process. Therefore, ‘sweet’ crude is more valuable compared to ‘sour’ crude. Mumbai High crude produced by ONGC is sweet crude.
19. Which of the following chemicals is also known as lachrymatory agent or lachrymator?
[A] Mustard Gas
[B] Tear gas
[C] Diborane
[D] Chlorine gas
Show Answer
Correct Answer: B [ Tear gas]
Notes:
Tear gas is also known as CS Gas. It acts as a lachrymatory agent. Tear gas irritate the mucous membrane of the eyes, nose, mouth and lungs, and causes tearing, coughing, burning and difficult breathing.
20. Which of the following laws is used as a rule to predict the solubility of gases in metals?
[A] Dalton’s Law
[B] Sievert’s law
[C] Graham’s law
[D] Henry’s law
Show Answer
Correct Answer: B [ Sievert’s law]
Notes:
Sievert’s law is used as a rule in physical metallurgy to predict the solubility of gases in metals.
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