Chemistry MCQ Questions with Answer for all Competitive Exams

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Chemistry MCQ Questions with Answer

 

Q81. Match List-I with List-II and select the correct answer using the code given below the lists:​

List-I (Naturally occurring substance)List-II (Elements present)
A. Diamond1. Calcium
B. Marble2. Silicon
C. Sand3. Aluminum
D. Ruby4. Carbon

Code: A B C D

(a)        3 1 2 4

(b)       4 2 1 3

(c)        2 1 3 4

(d)       4 1 2 3

Answer: ​(b)​

Explanation: Graphite is used as a moderator in nuclear reactors. The nuclear reactor provides us Nuclear energy for structural works. Heavy water is also used as a moderator in Nuclear reactors.

Q82. Vinegar is an aqueous solution of​

​(a)​ Oxalic acid ​

(b)​ Citric acid ​

(c)​ Hydrochloric acid ​

(d)​ Acetic acid

Answer: (d)​

Explanation: Acids are those substances in which Hydrogen is found and they produce Hydrogen ion in aqueous solution. We use many natural acids in our usual life. In lemon, Orange, and grapes citric acid is found while malic acids are found in raw apples, and in milk lactic Acid is found while in Vinegar Acetic Acid (CH3COOH) is found.

Q83. ​Iodised salt contains –​​​

​(a)​ Free iodine

​(b)​ Calcium iodine ​

(c)​ Magnesium iodine ​

(d)​ Potassium Iodine ​

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

Answer: (d) ​

Explanation: Generally, iodized salt contains Iodine either as Potassium Iodide or Potassium Iodate.

Q84. The important metal used with iron to produce stainless steel is ​

(a) ​Carbon ​

(b)​ Tin

​(c)​ Chromium

​(d)​ Aluminium

Answer: (c)​

Explanation: Stainless steel contains sufficient chromium to form a passive film of chromium oxide, which prevents further surface corrosion by blocking oxygen diffusion to the steel surface and blocks corrosion from spreading into the metal’s internal structure.

Q85. Which of the following copper alloys is used for the manufacture of springs and suspension filaments in electrical instruments? ​

(a)​ Bronze ​

(b)​ Aluminium bronze ​

(c)​ German silver ​

(d)​ Phosphor bronze

Answer: (d)​

Explanation: Phosphor bronze is used for manufacture of springs and suspension filaments in electrical instruments.

Q86. Which of the following is correctly matched? ​

(a)​ Aluminium-Haematite

​(b) ​Lead-Galena ​

(c)​ Iron-Bauxite ​

(d) ​Magnesium-Malachite

Answer: ​(b)​

Explanation:

Haematite – Iron (Fe2O3) ​​

Galena – Lead (PbS) ​​

Bauxite – Aluminium (Al (OH) 3) ​​

Malachite – Copper (Cu2CO3 (OH) 2)

Q87. Which of the following contains both ionic and covalent bonds?

(a) H2O

(b) NaOH

(c) C6H6

(d)CO2

Answer: (b)

Explanation: NaOH molecule contains both ionic and covalent bonds. In the NaOH molecule, Na has a positive charge while OH has a negative charge. The ionic bond is present between Na+ and OH. The covalent bond is present between O and H atoms in OH.

Q88. Which one of the following was used as a chemical weapon in the First World War?

(a) Carbon monoxide

(b) Hydrogen cyanide

(c) Mustard gas

(d) Water gas

Answer: (c)

Explanation: The most effective gas of the First World War was mustard gas a vesicant, which was introduced by Germany in July 1917. Mustard gas is not a particularly effective killing agent but the skin of its victims got blistered, their eyes became very sore and they began to vomit. Mustard gas caused internal and external bleeding and attacked the bronchial tubes.

Q89. Charcoal is used in water treatment as a/an–

(a) Solvent

(b) Absorbent

(c) Coagulant

(d) Adsorbent

Answer: (d)

Explanation: Charcoal or coal of wood is a black Brownish Product that is formed when wood or bone is combusted in the absence of oxygen and water. Volatile constituents from animals and vegetation are removed. Charcoal is used as an adsorbent in water treatment because charcoal adsorbs the pollutants present in water.

Q90. CNG used in automobiles to check pollution mainly consists of

​(a)​ CH4

​(b) ​CO2

​(c)​ N2

(d)​ H2

Answer: (a)

Explanation: ​Natural gas is 95 percent Methane (CH4) and have four other hydrocarbons: ​​Ethane (C2H6) – 2.5%, Propane (C3H8) – 0.2%, Butane (C4H10) – 0.06%, Pentanes Plus Decane (C5H12 + C10H22) – 0.02%. It also contains small amounts of: Nitrogen (N2) – 1.6%, Carbon Dioxide (CO2) – 0.7%, Hydrogen Sulphide (H2S) – trace, Water (H2O) – trace

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