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
21. What is the chemical formula for Sodium Chloride (Salt)?
[A] NaCl2
[B] NaCl
[C] Na2Cl
[D] Na2c
Show Answer
Correct Answer: B [NaCl]
Notes:
Sodium chloride, commonly known as salt, is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions.
22. The deficiency of which of the following minerals causes goiter?
[A] Sulphur
[B] Iodine
[C] Calcium
[D] Vitamin A
Show Answer
Correct Answer: B [Iodine]
Notes:
A goiter is an enlarged thyroid gland that causes the neck to swell. Iodine deficiency is the major cause of goiter worldwide. The thyroid gland needs iodine to manufacture thyroid hormones, which regulate the metabolism.
Goiter is often harmless but symptoms can occur, and treatment may be required depending on the size and type of goiter.
23. With which of the following materials the tape of the tape-recorder is coated?
[A] Cooper sulphate
[B] Mica
[C] Ferromagnetic powder
[D] Zinc oxide
Show Answer
Correct Answer: C [Ferromagnetic powder]
Notes:
The tape itself is actually very simple. It consists of a thin plastic base material, and bonded to this base is a coating of ferric oxide powder. The oxide is normally mixed with a binder to attach it to the plastic, and it also includes some sort of dry lubricant to avoid wearing out the recorder.
24. Galvanized iron sheets are protected from rusting due to the presence of a layer of which of the following elements?
[A] Lead
[B] Chromium
[C] Zinc
[D] Tin
Show Answer
Correct Answer: C [Zinc]
Notes:
Galvanization or galvanizing is the process of applying a protective zinc coating to steel or iron, to prevent rusting. The most common method is hot-dip galvanizing, in which the parts are submerged in a bath of molten zinc.
25. Cobalt-60 is commonly used in radiation therapy because it emits?
[A] alpha rays.
[B] Beta rays.
[C] Gamma rays.
[D] X-rays.
Show Answer
Correct Answer: C [Gamma rays.]
Notes:
Cobalt-60 (60Co) has been used for radiotherapy cancer treatment, food irradiation and industrial applications. As cobalt-60 decays into a stable nickel-60 isotope, two wavelengths of high-energy gamma-rays are emitted (1.17 and 1.33 MeV- average of 1.25 MeV used).
26. Consider the following statements :
Glass can be etched or scratched by
I. diamond.
II. hydrofluoric acid.
III. aquaregia.
IV. cone, sulphuric acid.
Which of these statements are correct?
[A] I and IV
[B] II and III
[C] I and II
[D] II and IV
Show Answer
Correct Answer: C [I and II]
Notes:
Glass is etched by applying a caustic compound to the glass surface. The compound chemically eats away at the glass substrate (borosilicate), and causes etching in the glass surface. Another method involves physically grinding the glass surface with an abrasive, like a grinding wheel. The surface is worn away where the wheel hits, and the etched surface remains. Some very artistic designs can be created with both methods. Glass can be etched or scratched by diamond and hydrofluoric acid.
27. Match List I (Drugs / Chemicals) with List II (Their uses) and select the correct answer using the codes given below the Lists:
|
List I |
List II |
|
I. Atropine |
(A) Local anaesthesia |
|
II. Ether |
(B) Heart trouble |
|
III. Nitroglycerine |
(C) Dilation of pupil |
|
IV. Pyrethrin |
(D) Mosquito control |
Codes:
[A] I-A, II-C, III-B, IV-D
[B] I-A, II-C, III-D, IV-B
[C] I-C, II-A, III-D, IV-B
[D] I-C, II-A, III-B, IV-D
Show Answer
Correct Answer: D [I-C, II-A, III-B, IV-D]
Notes:
Ether is used as an anesthesia at the time of surgery to prevent pain. Atropine is used as eye drops to dilate the pupil before eye examination. Nitroglycerine is widely used in the treatment of heart. Pyrethrin is biodegradable, non-persistent pesticide which is used to kill mosquitoes, fleas and other insects.
28. An aqueous solution of copper sulphate is acidic in nature because the salt undergoes?
[A] dialysis
[B] electrolysis
[C] hydrolysis
[D] photolysis
Show Answer
Correct Answer: C [hydrolysis]
Notes:
Aqueous solution of copper sulphate is acidic in nature because copper sulphate on dissolving with water, following chemical reaction takes place CuSO4(s) + 2H2O – Cu(OH)2(l) + H2SO4(aq) Now as we can see in above chemical equation the sulphuric acid generated is strong mineral acid which results into increase in acidity of solution. Thus aqueous solution of copper sulphate is acidic in nature.
29. What is the name of the female from Mesopotamian Civilization who is also known to be world’s first recorded chemist?
[A] Berossus
[B] Tapputi
[C] Abba b. Martha
[D] Gobryas
Show Answer
Correct Answer: B [Tapputi]
Notes:
Tapputi or Tapputi-Belatekallim is world’s first recorded chemist. She was a perfume-maker mentioned in a cuneiform tablet dated around 1200 BC in Babylonian Mesopotamia.
30. Which of the following is correct combination of masses of the three sub-atomic particles?
[A] Electron – 0. 00055 amu; Proton – 1.0078 amu; Neutron – 1.0083 amu
[B] Electron – 0. 00055 amu; Proton – 1.0083 amu; Neutron – 1.0078 amu
[C] Electron – 0. 00055 amu; Proton – 1.0078 amu; Neutron – 1.0078 amu
[D] Electron – 0. 00055 amu; Proton – 1.0083 amu; Neutron – 1.0083 amu
Show Answer
Correct Answer: A [Electron – 0. 00055 amu; Proton – 1.0078 amu; Neutron – 1.0083 amu]
Notes:
The correct mass of Electron is 0. 00055 amu; Proton is 1.0078 amu and Neutron is 1.0083 amu. Kindly note mass of neutron is slightly more than that of Proton.
