Chemistry MCQ Questions with Answer for all Competitive Exams

Share on facebook
Facebook
Share on twitter
Twitter
Share on telegram
Telegram
Share on whatsapp
WhatsApp
Share on pinterest
Pinterest
Share on reddit
Reddit
Share on tumblr
Tumblr

Chemistry MCQ Questions with Answer

 

Q11. The gas used in the manufacture of Vanaspati Ghee from Vanasapati Oil is –

(a) Hydrogen

(b) Oxygen

(c) Nitrogen

(d) Carbon dioxide

(e) None of the above / more than one of the above

Answer: ​(a)​

Explanation: Vanaspati ghee is manufactured from vegetable oil by a process called ‘hydrogenation’. Bypassing hydrogen gas. Vegetable Oil contains unsaturated fatty acids; upon hydrogenation, it is converted into saturated fatty acids to form vanaspati ghee.

Q12. Discovery of the nucleus of an atom was due to the experiment carried out by ​

(a)​ Bohr ​

(b)​ Rutherford

​(c)​ Moseley ​

(d) ​Thomson

Answer: (b)​

Explanation: Rutherford determined that the particles that made up the gold foil must consist mostly of empty space since most of the alpha particles passed through. However, some regions of the gold must have been too dense to allow the alpha particles through, and this heavy part of the atom was what Rutherford called the nucleus. He concluded that it was the nucleus that held most of the atom’s mass.

Q13. The chemical used as a ‘fixer’ in photography is

(a) Sodium sulfate

(b) Sodium thiosulphate

(c) Ammonium persulphate

(d) Borax

Answer: (b)

Explanation: Sodium thiosulphate is used in photography as a fixer. It removes Ag from the negative by dissolving unexposed silver bromide resulting in the formation of the complex.

AgBr + 2Na2S2O3   → Na3 [Ag (S2O3)2] + NaBr

Q14. Match the following pair:-

NatureSubstance
1. Acidic(a) Distill water
2. Basic(b) Carbonated drink
3. Neutral(c) Soap

(a) 1 – a, 2 – c, 3 – b

(b) 1 – b, 2 – c, 3 – a

(c) 1 – a, 2 – b, 3 – c

(d) 1 – c, 2 – a, 3 – b

Answer: (b)

Explanation:

1. Acidic → Carbonated drink
2. Basic → Soap
3. Neutral → Distil water

The carbonated drink is Acidic in nature due to the presence of H2CO3 acid. Soaps are Sodium or Potassium salts of fatty acids, which provide basic nature. Distill water has no salts or impurity so it is neither acidic nor basic i.e. neutral.

Q15. What is the common name of Calcium Hypochlorite?

(a) Water

(b) Bleaching powder

(c) Baking soda

(d) Baking powder

Answer: (b)

Explanation: Calcium Hypochlorite is bleaching powder. Its chemical formula is CaOCl2. It is used in the disinfection of water and as a bleaching agent.

Q16. The atoms, in which the number of protons is the same but the number of neutrons is different, are known as

(a) ​Isotopes ​

(b) ​Isobars

​(c)​ Isomers

​(d) ​Isotones

Answer: ​(a)​

Explanation: In isotopes electrons and protons are found in equal Number white the number of Neutron is different.

Also Read: General Science: Biology MCQ Question and Answer

Q17. The strength of hydrogen bonding in O, F, S, Cl, and N is in the order:

(a) Cl < S < N < O < F

(b) Cl < F < S < N < O

(c) Cl < N < S < O < F

(d) Cl < O < S < N < F

Ans. (a)

Explanation: Strength of a Hydrogen bonding, H……M increases with the increase in the electro negativity of M–atom. Out of the given atoms, Cl– does not form H–bond while the strength of H-bonding of other atoms is in the order S <N < O < F, since the electro negativity of these atoms also increases in the same order S (2.5) < N (3.0) < O (3.5) < F (4.0)

Q18. What happens when one s and one p orbital is hybridized?

(a) We get three orbital in a plane

(b) We get two orbital at 180 degrees

(c) We get two mutually perpendicular orbital

(d) We get four orbital directed tetrahedral

Answer: (b)

Explanation: Molecular orbital (MO) Theory was developed by F. Hund R.S. Mulliken in 1932. According to this theory – The number of molecular orbitals formed is equal to the number of combining orbital. When two atomic orbital combine, two molecular orbitals is formed.

Q19. Match List-I with List-II and select the correct answer using the codes given below the lists:

List-IList-II
A. German silver1. Tin
B. Solder2. Nickel
C. Bleaching powder3. Sodium
D. Hypo4. Chlorine

Codes:

(a) A-1; B-2; C-4; D-3

(b) A-2; B-1; C-3; D-4

(c) A-1; B-2; C-3; D-4

(d) A-2; B-1; C-4; D-3

Answer: (d)

Explanation: German silver has a color resembling silver, but is an alloy of primarily copper, nickel, and zinc. Solder is an alloy of tin, antimony, copper, and lead. Bleaching powder contains calcium chloride and calcium hypochlorite, used in solution as a bleach. Bleaching powder is sold on the basis of available chlorine, which is liberated when it is treated with dilute acid. It is used for bleaching paper pulps and fabrics and for sterilizing water. The Hypo solution used in iodometric titration is sodium thiosulphate (Na2S2O3).

Q20. Oils are purified by ​

(a)​ Fractional distillation

​(b)​ Steam distillation

​(c)​ Crystallization

​(d)​ Vacuum distillation

Answer: (b)​

Explanation: Oils are purified by steam distillation. In the steam distillation process, steam is bubbled through a heated mixture of raw material. Some of the target components will vaporize which are coded and condensed yielding a layer of oil and a layer of water.

Pages ( 2 of 10 ): « Previous1 2 3 ... 10Next »
error: Content is protected !!