General Science Questions (MCQs) for Competitive Examinations
General Science Multiple choice questions for GK paper in SSC, NDA, CDS, UPSC, UPPSC and State PSC Examinations. These questions are part of GKToday’s 35000+ MCQs Bank Course in GKToday Android App
21. What is the octane number of iso-octane?
Show Answer
Correct Answer: C [100]
Notes:
Octane number, also known as octane rating, are based on a scale on which iso-octane is 100, which means minimal knock, and heptane is 0. The higher the octane number, the more compression required for fuel ignition.
22. Which element has the narrowest liquid range?
[A] Helium
[B] Fluorine
[C] Argon
[D] Neon
Show Answer
Correct Answer: D [ Neon ]
Notes:
Neon has the narrowest liquid range of all the elements. The liquid range of a substance is possible range of temperature where liquid is allowed to exist.
23. Which of the following non-metals is most electronegative?
[A] Neon
[B] Fluorine
[C] Chlorine
[D] Oxygen
Show Answer
Correct Answer: B [ Fluorine ]
Notes:
Fluorine is the most electronegative element among all. Oxygen is the 2nd most electronegative element. Francium is one of the least electronegative element.
24. What are the structures formed by the soap molecules, during cleansing, known as?
[A] Stereates
[B] Esters
[C] Micelles
[D] Tubes
Show Answer
Correct Answer: C [Micelles]
Notes:
The ionic-end of soap dissolves in water while the carbon chain dissolves in oil. The soap molecules form structures called micelles where one end of the molecules is towards the oil droplet while the ionic-end faces outside.
25. Which of the following detergents is a cationic detergent?
[A] Sodium dodecylbenzenesulphonates
[B] Cetyltrimethyl ammonium bromide
[C] Both a and b
[D] None of the above
Show Answer
Correct Answer: B [Cetyltrimethyl ammonium bromide]
Notes:
Cetyltrimethyl ammonium bromide is an example of cationic detergent whereas Sodium dodecylbenzenesulphonates is an example of anionic detergent.
26. What is the total number of chromosomes in a normal human being?
Show Answer
Correct Answer: C [46]
Notes:
In humans, each cell normally contains 23 pairs of chromosomes, for a total of 46, of which 22 pairs, called autosomes, look the same in both males and females.
27. Chemotaxis is a phenomenon of__?
[A] swimming away of bacteria
[B] swimming towards a bacteria
[C] swimming away or towards of bacteria in presence of chemical compound
[D] All of the above
Show Answer
Correct Answer: C [swimming away or towards of bacteria in presence of chemical compound]
Notes:
Chemotaxis is a phenomenon of swimming away or towards of bacteria in presence of chemical compound.
28. Which of the following is a calyx?
[A] the second whorl of a flower
[B] the third whorl of the flower
[C] the outermost whorl of a flower
[D] None of these
Show Answer
Correct Answer: C [the outermost whorl of a flower]
Notes:
The calyx is the outermost whorl of a flower, consisting of sepals, small leaves present at the base of the flower. These protect the flowering clump against mechanical injury and drying. The calyx in some plants is colored sepals called petaloid.
29. Why are xylem cells considered dead?
[A] vessel elements have no organelles
[B] xylem tissues are highly lignified and scalarified
[C] Both 1 and 2
[D] Neither 1 nor 2
Show Answer
Correct Answer: C [Both 1 and 2]
Notes:
Xylem cells are made up of a long chain of dead cells and are known as vessel elements. Vessel elements have no organs. Components of xylem tissues are highly lignified and sclerized. Therefore, xylem cells are considered dead.
30. The material covering the bones of reptiles is?
[A] Calcium
[B] Chitin
[C] Keratin
[D] None
Show Answer
Correct Answer: C [Keratin]
Notes:
The material covering the bones of reptiles is Keratin and their skin is dry, and rough, without any glands.
