Chemistry MCQ Questions with Answer for all Competitive Exams

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Chemistry MCQ Questions with Answer


Q91. The gas which turns into Liquid at the lowest temperature among the following is–

(a) Hydrogen

(b) Oxygen

(c) Helium

(d) Nitrogen

Answer: (a)

Explanation: At the lowest temperature Hydrogen turns into Liquid.

Q92. Bio-gas mainly consists of ​

(a)​ Carbon dioxide and hydrogen ​

(b)​ Hydrogen and methane ​

(c)​ Carbon dioxide and methane ​

(d)​ Hydrogen and oxygen

Answer: ​(c)​

Explanation: Biogas is primarily a mixture of methane (CH4) and inert carbon dioxide gas (CO2). The gas is produced by the anaerobic digestion or fermentation of organic matter like manure, sewage sludge, municipal solid waste, biodegradable waste, etc. It is a clean and renewable fuel.

Q93. The order of appearance of the following with increasing temperature during the refining of crude oil is ____

​(a)​ Kerosene, gasoline, diesel ​

(b)​ Diesel, gasoline, kerosene ​

(c)​ Gasoline, kerosene, diesel ​

(d)​ Gasoline, diesel, kerosene

Answer: (c)​

Explanation: Petroleum products are usually grouped into three categories: light distillates (LPG, gasoline, and naphtha), middle distillates (kerosene, diesel), heavy distillates, and residuum (heavy fuel oil, lubricating oils, wax, and asphalt). Hence, the correct option would be Gasoline, kerosene, diesel.

Q94. Assertion (A): Formic acid is a stronger acid than acetic acid.

Reason (R): Formic acid is an organic acid.

(a) Both A and R are true and R is the correct explanation of A

(b) Both A and R are true but R is not a correct explanation of A

(c) A is true but R is false

(d) A is false but R is true

Answer: (b)

Explanation: Formic acid is stronger than acetic acid due to its chemical composition. Formic acid is an organic acid as well as active acid in an organic acid.

Q95. Which of the following do not contain nitrogen element?

​1.​ Superphosphate of lime ​

2.​ Urea ​

​3. Indian saltpeter ​

4.​ Chile saltpeter ​

(a)​ 1, 3 and 4 ​

(b)​ 1 and 3 ​

(c)​ 1 only ​

(d)​ 3 only

Answer: ​(c)​

Explanation: Superphosphate of lime – Ca(H2PO4)2 ​​Urea – CO(NH2)2 ​​Indian saltpeter – KNO3 ​​Chile saltpeter – NaNO3

Q96. Match List-I with List-II and select the correct answer by using the codes given below the lists: [UP-PCS 2011]

A. Morphine1. Antiseptic
B. Sodium2. Alloy
C. Boric Acid3. Analgesic
D. German Silver4. Kerosene oil

Code: A B C D

(a)        4 3 1 2

(b)       2 4 3 1

(c)        3 1 4 2

(d)       3 4 1 2

Answer: (d)​

Explanation: Correct matching will be as following:

List – IList –II
A. Morphine3. Analgesic
B. Sodium4. Kerosene oil
C. Boric Acid1. Antiseptic
D. German Silver2. Alloy

Q97. What is Bisphenol (BPA)?

(a) A medical test for detecting cancer

(b) A test for testing the use of drugs to improve performance by athletes

(c) A chemical used for the development of food packaging materials

(d) A special type of alloy steel

Answer: (c)

Explanation: Bisphenol A, commonly abbreviated as BPA, is an organic compound with two phenol functional groups. Bisphenol A is used primarily to make plastics which is used in making food packaging material. It is a key monomer in the production of epoxy resins and used to make polycarbonate plastic. Polycarbonate plastic, which is clear and nearly shatter-proof, is used to make a variety of common products including baby and water bottles, sports equipment, medical and dental devices, dental fillings and sealants, eyeglass lenses, CDs and DVDs, and household electronics.

Q98. Which one of the following substances are used in the manufacture of safety matches?​​[NDA/NA 2008 -II]

​(a)​ Red phosphorus ​

(b)​ White phosphorus ​

(c)​ Phosphorus trioxide (P203)

(d) ​Black phosphorus

Answer: (a) ​

Explanation: Red phosphorus is mostly used in the manufacture of safety matches and in making smoke bombs.

Q99. Which one among the following does not have an allotrope? ​

(a) ​Oxygen ​

(b) ​Sulphur ​

(c) ​Nitrogen ​

(d)​ Carbon

Answer: (c)​

Explanation: Unstable allotropes of nitrogen consisting of more than two nitrogen atoms have been produced in the laboratory, like N3 and N4. Under extremely high pressures (1.1 million atm) and high temperatures (2000 K), as produced under diamond anvil conditions, nitrogen polymerizes into the single-bonded diamond crystal structure, an allotrope nicknamed “nitrogen diamond”.

Q100. Silicon is used in ​

(a)​ Solar energy devices ​

(b)​ Semiconductors

​(c)​ Transistors

​(d) ​All of these

Answer: (d)​

Explanation: Silicon is a semiconductor that means that unlike metal its electrical conductivity increases with temperature. As a semiconductor, silicon (Si) is used to make transistor which amplifies or switch electrical currents.

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