Chemistry MCQs
Chemistry Objective (Multiple Choice) General Knowledge Questions & Answers for SSC-CGL, UPPSC, UPSC, NDA, CDS and UPSC Civil Services Prelims Examination. These questions are part of GKToday’s 35000+ MCQs Bank Course in GKToday Android App
11. What is Tyndall effect?
[A] scattering of a beam of light by the particles of a suspension
[B] refraction of a beam of light by the particles of a solution
[C] scattering of a beam of light by the particles of a colloid
[D] reflection of a beam of light by the particles of a suspension
Show Answer
Correct Answer: C [scattering of a beam of light by the particles of a colloid]
Notes:
The scattering of a beam of light by the particles of a colloid is called the Tyndall effect.
12. Which of the following quantum number is also known as orbital angular momentum?
[A] Principal quantum number
[B] Azimuthal quantum number
[C] Magnetic quantum number
[D] Electron spin quantum number
Show Answer
Correct Answer: B [Azimuthal quantum number]
Notes:
Azimuthal quantum number is also known as orbital angular momentum or subsidiary quantum number. It is represented by ‘l’.
13. Which of the following gas is used to prevent the chips from getting oxidised?
[A] Oxygen
[B] Nitrogen
[C] Helium
[D] Lithium
Show Answer
Correct Answer: B [Nitrogen]
Notes:
The chips manufacturers usually flush bags of chips with gas such as nitrogen to prevent the chips from getting oxidised.
14. What is the general trend for first ionisation enthalpy in a group of the periodic table as we move from top to bottom?
[A] It increases
[B] it decreases
[C] It is constant
[D] None of the above
Show Answer
Correct Answer: B [it decreases]
Notes:
The first ionization enthalpy generally increases as we go across a period and decreases as we descend in a group. ionization enthalpy represents the energy required to remove an electron from an isolated gaseous atom (X) in its ground state.
15. Which of the following elements has the largest atomic radii?
[A] Lithium
[B] Beryllium
[C] Boron
[D] Carbon
Show Answer
Correct Answer: A [Lithium]
Notes:
The atomic radius generally decreases across a period. Therefore, Lithium will have the largest atomic radii among the given elements as it is placed before others as we move from left to right in the periodic table.
16. Choose the correct statement about the covalent character of the ionic bond:
[A] It is directly proportional to the charge on the cation
[B] It is inversely proportional to the size of cation
[C] Both a and b
[D] None
Show Answer
Correct Answer: C [Both a and b]
Notes:
The smaller the size of the cation and the larger the size of the anion, the greater the covalent character of an ionic bond. Also, greater the charge on the cation, the greater the covalent character of the ionic bond.
17. What can we call the carbon atom present in Methane?
[A] primary carbon atom
[B] secondary carbon atom
[C] tertiary carbon atom
[D] quaternary carbon atom
Show Answer
Correct Answer: A [primary carbon atom]
Notes:
Carbon atom attached to no other carbon atom as in methane or to only one carbon atom as in ethane is called primary carbon atom.
18. Ethanoic acid is the main constituent of which of the following substances?
[A] Soap
[B] Vinegar
[C] Wine
[D] Curd
Show Answer
Correct Answer: B [Vinegar]
Notes:
Common name of Ethanoic acid is acetic acid and its main constituent of is a colourless liquid. 5-8% solution of acetic acid in water is called vinegar and is used widely as a preservative in pickles. The melting point of pure ethanoic acid is 290 K.
19. Which of the following compound was used to isolate Potassium metal for the first time?
[A] Potassium oxide
[B] Potassium peroxide
[C] Potassium hydroxide
[D] Potassium superoxide
Show Answer
Correct Answer: C [Potassium hydroxide]
Notes:
Potassium hydroxide (caustic potash) was used first to isolate Potassium metal. It was done by Humphry Davy through electrolysis of molten KOH in 1807.
20. What is the colour of Rhombic sulphur?
[A] Red
[B] Yellow
[C] Black
[D] Colorless
Show Answer
Correct Answer: B [ Yellow ]
Notes:
Rhombic sulphur is an allotrope of Sulphur which is yellow in colour. Rhombic sulphur crystals are formed on evaporating the solution of roll sulphur. It is also known as alpha-sulphur.
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