Chemistry MCQs
Chemistry Objective (Multiple Choice) General Knowledge Questions & Answers for SSC-CGL, UPPSC, UPSC, NDA, CDS and UPSC Civil Services Prelims Examination.
1. A cotton wick dipped in pure honey when ignited with a matchstick will ______?
[A] Burn steadily
[B] Burn with a cracking sound
[C] Not burn at all
[D] Burn producing a large amount of smoke
Show Answer
Correct Answer: A [Burn steadily]
Notes:
A cotton wick soaked in pure honey, when lit with a matchstick, will burn consistently. This is primarily due to the high sugar content of the honey acting as fuel for the flame. Contrary to common misconceptions, honey doesn’t produce much smoke or any unusual sounds during combustion.
2. What type of fiber is Rayon considered?
[A] A synthetic fiber
[B] A natural fiber
[C] A semi-synthetic fiber
[D] A synthetic detergent
Show Answer
Correct Answer: C [A semi-synthetic fiber]
Notes:
Rayon is considered a semi-synthetic fiber. It is made by regenerating natural materials into a usable form. Rayon fibers are derived from cellulose obtained from wood or related agricultural products. It was first commercially produced in 1905 by the Swiss firm J. R. Geigy, originally under the name “artificial silk”
3. Which colour does cobalt oxide impart to glass?
[A] Brown
[B] Blue
[C] Red
[D] Yellow
Show Answer
Correct Answer: B [Blue]
Notes:
Cobalt Oxide is commonly used to create a distinctive blue hue in glasses and ceramics. The depth of the blue can be altered by changing the concentration of the oxide. In addition to being used for aesthetic purposes, Cobalt blue, which results from Cobalt Oxide, is also used because it absorbs certain wavelengths of light, making it useful for filtering out unwanted wavelengths.
4. Cassiterite is most important source of which of these metals?
[A] Nickel
[B] Tin
[C] Tungsten
[D] Silver
Show Answer
Correct Answer: B [Tin ]
Notes:
Cassiterite is a mineral that is primarily composed of tin dioxide (SnO2). It is the most important source of tin, and is also used as a semi-precious gemstone. Cassiterite is typically found in igneous and metamorphic rocks, and is often associated with other minerals such as quartz, feldspar, and mica. It has a high melting point and is resistant to weathering, making it a useful material for many industrial applications. The name “cassiterite” comes from the Greek word “kassiteros,” which means “tin.”
5. Which of the following elements have the lowest and highest boiling point in the Periodic table?
[A] Helium and Tungsten
[B] Hydrogen and Rhenium
[C] Helium and Rhenium
[D] Hydrogen and Tungsten
Show Answer
Correct Answer: C [ Helium and Rhenium]
Notes:
Helium has the lowest boiling point of all the elements at –452.074°F (–268.93°C) followed by hydrogen –423.16°F (–252.87°C). The highest boiling point for an element is that of Rhenium 10,104.8°F (5,596°C) followed by tungsten 10,031°F (5,555°C).
6. Which of the following element has the highest first ionization enthalpy?
[A] Magnesium
[B] Strontium
[C] Beryllium
[D] Barium
Show Answer
Correct Answer: C [Beryllium]
Notes:
The alkaline earth metals have low ionization enthalpies due to fairly large size of the atoms. Since the atomic size increases down the group, their ionization enthalpy decreases.
7. What do we call the energy required to remove loosely bound electron from an atom?
[A] Excitation energy
[B] Atom energy
[C] Ionization energy
[D] Shell energy
Show Answer
Correct Answer: C [Ionization energy]
Notes:
Ionization energy is the quantity of energy required to remove loosely bound electron from an atom.
8. Which of the following is the chemical formula of Carbonic acid?
[A] Ca CO2
[B] H2 CO3
[C] H3 CO4
[D] H CO3
Show Answer
Correct Answer: B [H2 CO3]
Notes:
Carbonic acid is a chemical compound with the chemical formula H2 CO3. Its find its use in many most aerated drinks, such as sodas and soft drinks.
9. What is the reason for the presence of the vast number of organic compounds in nature?
[A] Carbon exists in free state
[B] Catenation property of carbon
[C] Low atomic mass of carbon
[D] None of the above
Show Answer
Correct Answer: B [Catenation property of carbon]
Notes:
Because of the catenation property of carbon, vast number of organic compounds are present in nature. Catenation refers to the linkage of atoms of the same element into longer chains.
10. Which of the following is the product of the reaction between Ethanoic acid and Sodium hydrogen carbonate?
[A] Ethyne
[B] Sodium acetate
[C] Ethanol
[D] Sodium hydroxide
Show Answer
Correct Answer: B [Sodium acetate]
Notes:
Sodium acetate is produced when Ethanoic acid and Sodium hydrogen carbonate reacts with each other. Ethanoic acid reacts with carbonates and hydrogen carbonates to give rise to a salt, carbon dioxide and water.
