Chemistry MCQs
Chemistry Objective (Multiple Choice) General Knowledge Questions & Answers for SSC-CGL, UPPSC, UPSC, NDA, CDS and UPSC Civil Services Prelims Examination.
11. Which of the following is the correct order of the decreasing order of abundance of the elements in earth’s crust?
[A] Iron > Silicon > Oxygen >Aluminium
[B] Oxygen > Silicon > Aluminium > Iron
[C] Oxygen> Iron > Aluminium > Silicon
[D] Iron > Aluminium > Silicon > Oxygen
Show Answer
Correct Answer: B [Oxygen > Silicon > Aluminium > Iron]
Notes:
Oxygen is the most abundant element in the earth’s crust followed by Silicon, Aluminium and Iron. It comprises almost half of the mass of the earth’s crust.
12. Which of the following is not an ore of Zinc?
[A] Sphalerite
[B] Zincite
[C] Calamine
[D] Carnetite
Show Answer
Correct Answer: D [Carnetite]
Notes:
Carnetite is an ore of Uranium, where as Sphalerite(Zinc blende), Zincite and Calamine are some of the important ores of Zinc.
13. Which of the following is true about Rutherford model of atom?
[A] it explains how the electrons are distributed around the nucleus
[B] It cannot explain about the stability of an atom around the nucleus
[C] It tells us about the energies of the electrons around the nucleus
[D] All of the above
Show Answer
Correct Answer: B [It cannot explain about the stability of an atom around the nucleus]
Notes:
A serious limitation of the Rutherford model is that it says nothing about the electronic structure of atoms i.e., how the electrons are distributed around the nucleus and what are the energies of these electrons. Also, the Rutherford model cannot explain the stability of an atom.
14. Choose the correct statement about d-block elements:
[A] These are the elements of Group 3 to 10
[B] All of them are metals
[C] Both a and b
[D] None
Show Answer
Correct Answer: B [All of them are metals]
Notes:
d-block elements are the elements of Group 3 to 12 in the centre of the Periodic Table. All of them are metals. These are characterised by the filling of inner d orbitals by electrons.
15. Which of the following statements is correct?
[A] pH scale measure the hydrogen ion concentration
[B] pH of a neutral solution is 10
[C] Both a and b
[D] None
Show Answer
Correct Answer: A [pH scale measure the hydrogen ion concentration]
Notes:
pH scale is a scale for measuring hydrogen ion concentration in a solution, called pH scale has been developed. The p in pH stands for ‘potenz’ in German, meaning power. On the pH scale we can measure pH generally from 0 (very acidic) to 14 (very alkaline). The pH of a neutral solution is 7. Values less than 7 on the pH scale represent an acidic solution.
16. Which of the following chemical is produced when Ethene reacts with cold aqueous solution of Bayer’s reagent?
[A] Methanol
[B] Glycol
[C] Methanal
[D] Ethyne
Show Answer
Correct Answer: B [Glycol]
Notes:
Alkenes on reaction with cold, dilute, aqueous solution of potassium permanganate (Baeyer’s reagent) produce vicinal glycols.
17. Which of the following would come in use to treat diseased skin surfaces?
[A] Analgesics
[B] Antiseptics
[C] Antihistamines
[D] None of the above
Show Answer
Correct Answer: B [ Antiseptics]
Notes:
Antiseptics are applied to the living tissues such as wounds, cuts, ulcers and diseased skin surfaces. Examples of antiseptics are furacine, soframicine, etc
18. Cream gets separated out of milk when it is churned due to which of the following reasons?
[A] Gravitational pull
[B] Centripetal force
[C] Centrifugal force
[D] Frictional force
Show Answer
Correct Answer: C [Centrifugal force]
Notes:
When Milk is churned vigorously the cream from it is separated out due to Centrifugal Force. Churning physically agitates the cream until it ruptures the fragile membranes surrounding the milk fat.
19. Chewing gum is made from which of the following?
[A] Resin
[B] Polystyrene
[C] Polyvinyl acetate
[D] Latex
Show Answer
Correct Answer: D [Latex]
Notes:
Chewing gum was made of a substance called chicle mixed with flavorings. Chicle is a latex sap that comes from the sapodilla tree (native to Central America).
20. Which metal is responsible for Itai-Itai disease?
[A] Mercury
[B] Chromium
[C] Cadmium
[D] Nickel
Show Answer
Correct Answer: C [Cadmium]
Notes:
Cadmium poisoning can also cause softening of the bones and kidney failure. The cadmium was released into rivers by mining companies in the mountains, which were successfully sued for the damage. Itai-itai disease is known as one of the 4 Big Pollution Diseases of Japan.
