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
21. What is the body called which does not have any tendency to recover its original configuration, on the removal of deforming force?
[A] Perfectly plastic
[B] Perfectly elastic
[C] Perfectly ductile
[D] None of the above
Show Answer
Correct Answer: A [Perfectly plastic]
Notes:
Perfectly plastic: If the body does not have any tendency to recover its original configuration, on the removal of deforming force, it is said to be perfectly plastic. Paraffin wax, wet clay can be the closest example of the perfectly plastic body.
22. What is Young’s Modulus?
[A] ratio of longitudinal strain to normal stress
[B] product of normal stress of longitudinal strain
[C] ratio of normal stress to longitudinal strain
[D] ratio of normal stress to lateral strain
Show Answer
Correct Answer: C [ratio of normal stress to longitudinal strain]
Notes:
Young’s Modulus is defined as the ratio of normal stress to longitudinal strain within limit of proportionality. Y = normal stress/longitudinal strain
23. What is the order of distance for interatomic forces to be active?
[A] 10–7 metre
[B] 10–8 metre
[C] 10–9 metre
[D] 10–10 metre
Show Answer
Correct Answer: D [10–10 metre]
Notes:
The forces between the atoms because of the electrostatic interaction between the charges of the atoms are called interatomic forces. These forces are active if the distance between the two atoms is of the order of atomic size i.e. 10–10 metre. These forces are electrical in nature.
24. What is the order of distance for Vander Wall forces to be active?
[A] 10–6 metre
[B] 10–7 metre
[C] 10–8 metre
[D] 10–9 metre
Show Answer
Correct Answer: D [10–9 metre]
Notes:
The forces between the molecules because of the electrostatic interaction between the charges of the molecules are called intermolecular forces. These forces are also called Vander Waal forces. They are quite weak as compared to inter-atomic forces. These forces are also electrical in nature. They are active if the separation between two molecules is of the order of molecular size i.e. 10–9 metre.
25. What happens to the non-metallic character of elements in the p-block of the periodic table?
[A] non-metallic character decreases down the group
[B] non-metallic character increases down the group
[C] No fix pattern
[D] None
Show Answer
Correct Answer: A [non-metallic character decreases down the group]
Notes:
The non-metallic character of elements decreases down the group. In fact, the heaviest element in each p-block group is the most metallic in nature.
26. What is the general outer electron configuration of Group 13 elements?
[A] ns2 np2
[B] ns2
[C] ns2 np1
[D] ns2 np3
Show Answer
Correct Answer: C [ns2 np1]
Notes:
ns2 np1
27. Which of these is NOT an allotropic form of carbon?
[A] Diamond
[B] Graphite
[C] Fullerene
[D] None of the above
Show Answer
Correct Answer: D [None of the above]
Notes:
Carbon exhibits many allotropic forms; both crystalline as well as amorphous. Diamond and graphite are two well-known crystalline forms of carbon. In 1985, third form of carbon known as fullerenes was discovered.
28. Which of the following element is NOT an alkaline earth metal?
[A] Magnesium
[B] Strontium
[C] Barium
[D] Beryllium
Show Answer
Correct Answer: D [Beryllium]
Notes:
The elements of Group 2 include beryllium, magnesium, calcium, strontium, barium and radium. These elements with the exception of beryllium are commonly known as the alkaline earth metals.
29. What is the half life of the longest lived isotope of Francium?
[A] 1 minute
[B] 21 minute
[C] 21 hours
[D] 100 days
Show Answer
Correct Answer: B [21 minute]
Notes:
Francium is highly radioactive. its longest-lived isotope 223Fr has a half-life of only 21 minutes.
30. Which of the following is NOT correct about Group 14 elements?
[A] All of them are solids
[B] Melting points are much higher than those of corresponding elements of group 13
[C] Carbon is a non-metal
[D] Germanium is a metal
Show Answer
Correct Answer: D [Germanium is a metal]
Notes:
All members of group 14 are solids. Carbon and silicon are non-metals, germanium is a metalloid, whereas tin and lead are soft metals. Melting points and boiling points of group 14 elements are much higher than those of corresponding elements of group 13.
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