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. With reference to LNG (Liquefied Natural Gas), which among the following observations is / are correct?
1.LNG is odourless and colourless
2.LNG is generally non-corrosive and non-toxic
3.The weight of certain volume of LNG is around half of weight of same volume of water
Choose 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:
LNG is liquefied natural gas. Natural gas is a mixture of hydrocarbons, composed primarily of methane. When natural gas is cooled to a temperature of approximately – 260 degree F at atmospheric pressure, it condenses to a liquid called liquefied natural gas (LNG). One volume of this liquid takes up about 1/600th the volume of natural gas at a stove burner tip. LNG weighs about 45% as much as water of a similar volume. LNG is odourless, colourless, non-corrosive, and non-toxic. Natural gas is a naturally occurring gas mixture composed primarily of methane (typically, at least 90%), but may also contain ethane, propane and heavier hydrocarbons. LNG does not have an odor. However, manufacturers often add traces of a substance like T-butyl mercaptan to give it a foul smell.
12. The alloy steel containing chromium to resist rusting is known as stainless steel. What is played by Chromium in stainless steel?
- Chromium does not rust, so it works as protecting cover
- Chromium reacts with Iron to make a compound that is not affected by Oxygen
Select the correct option from the codes given below:
[A] Only 1
[B] Only 2
[C] Both 1 & 2
[D] Neither 1 nor 2
Show Answer
Correct Answer: D [ Neither 1 nor 2]
Notes:
What happens is this: Chromium basically works like a sacrificial metal. It rusts first but the rusting chromium doesn’t crumble apart. Rather, it would form an invisibly thin layer that protects the iron underneath. On the other hand, the nickel in stainless steel helps hold this protective layer of chromium rust in place. We also note here that the chromium and nickel are present throughout stainless steel, not just on the surface. Because of this, the microscopic layer will form itself anew, even when the steel is cut or scratched.
13. Nerve agents are a class of:
[A] phosphorus-containing organic chemicals
[B] sulphur-containing organic chemicals
[C] osmium-containing organic compounds
[D] radon-containing organic compounds
Show Answer
Correct Answer: A [ phosphorus-containing organic chemicals]
Notes:
Nerve agents are a class of phosphorus containing organic compounds.
14. Which of the following is not a metalloid?
[A] Boron
[B] Silicon
[C] Germanium
[D] Titanium
Show Answer
Correct Answer: D [ Titanium]
Notes:
The most commonly recognised metalloids are boron, silicon, germanium, arsenic, antimony and tellurium. The other less recognised metalloids are: carbon, aluminium, selenium, polonium and astatine.Titanium is a lustrous transition metal with a silver color, low density and high strength.
15. Consider the following differences between metals and non-metals:
- While the oxides of metals are basic in nature, oxides of non-metals are acidic in nature
- While most of the metals are solid at room temperature, most of non-metals are gaseous at room temperature
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: C [ Both 1 & 2]
Notes:
Both are correct statements
16. Consider the following differences between Sodium Vapour Lamp and Mercury Lamp:
- While sodium vapour lamp gives out a yellowish colour illumination, and a mercury vapour lamp that gives out a white colour illumination
- The light in sodium vapour lamp is from an atomic emission process whereas in mercury vapour lamp it is from fluorescence emission
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: C [ Both 1 & 2]
Notes:
Both are correct statements
17. Which of the following are used as chemical agents in war?
- Mustard Gas
- Phosgene
- Sarin
- VX
Select the correct option from codes given below:
[A] 1 & 3 Only
[B] 1, 3 & 4 Only
[C] 2 & 4 Only
[D] 1, 2, 3 & 4
Show Answer
Correct Answer: D [ 1, 2, 3 & 4]
Notes:
Chemical weapons are called “poorman’s bomb”. These cause catastrophic damage, and are easy to produce. Sarin is a colorless and odourless agent, and is extremely potent. It was used in Damascus in 2013. Mustard Gas is possibly the most commonly used chemical agent and gets its name from the distinctive odour of rotten mustard. It is less potent and usually only 5 to 10 percent people exposed to it usually die. It was widely used during Second World War. VX is a nerve agent which is odourless and appears as brownish oily substance.
18. Consider the following statements:
- Sucrose is the sweetest of all naturally occurring carbohydrates
- Acetylene is the basic chemical building block of natural rubber
Which of 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: D [Neither 1 nor 2 ]
Notes:
Sucrose is the sweetest of all naturally occurring carbohydrates This is incorrect. Correct sugar would be fructose. Acetylene is the basic chemical building block of natural rubber This is incorrect. The purified form of natural rubber is the chemical polyisoprene, which can also be produced synthetically. Natural rubber is used extensively in many applications and products, as is synthetic rubber. It is normally very stretchy and flexible and extremely waterproof.
19. Consider the following differences between Soaps and Detergents:
- Detergents are carbonic compounds which are not alkaline, Soap are made from fat and alkali
- Soaps are biodegradable while detergents are not biodegradable
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: C [Both 1 & 2]
Notes:
Both are correct statementsSoaps are prepared from animal fats or vegetable oils. Detergents are prepared from hydrocarbons obtained from coal and petroleum. While soaps are biodegradable, detergents are not biodegradable.
20. Consider the following statements about the Coalbed Methane:
- It is called 'sweet gas' because of its lack of hydrogen sulphide
- It contains very little heavier hydrocarbons such as propane or butane
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: C [Both 1 & 2]
Notes:
Both are correct statements
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