Chemistry MCQs
Chemistry Objective (Multiple Choice) General Knowledge Questions & Answers for SSC-CGL, UPPSC, UPSC, NDA, CDS and UPSC Civil Services Prelims Examination.
1. Which of the following is the most active chemically?
[A] Chlorine
[B] Flourine
[C] Lithium
[D] Iodine
Show Answer
Correct Answer: B [Flourine]
Notes:
Fluorine is most active because it has the highest electronegativity.
2. Trimethylxanthine is a chemical name of a stimulant which is found in tea and coffee. What is the popular name?
[A] Thein
[B] Caffeine
[C] Theobromine
[D] Theophylline
Show Answer
Correct Answer: B [Caffeine]
Notes:
Caffeine (1, 3, 7-trimethylxanthine) also known as ancient wonder drug is a basically a neurostimulant easily available all over the world and is used in different products like tea, coffee, analgesic adjuvant, soft drinks and many dietary supplements.
3. What is the common name of Calcium Sulphate Hemihydrate?
[A] Bleaching powder
[B] Slaked lime
[C] Plaster of paris
[D] Detergent
Show Answer
Correct Answer: C [Plaster of paris]
Notes:
Plaster of Paris is calcium sulphate hemihydrate. The formula is given as, CaSO4.1/2 H2O or (2 CaSO4) . H2O. The powder is called plaster of Paris, because the gypsum which was used to get the powder was mainly found in Paris.
4. Which of the following best describes the nature of Froth and Foam?
[A] Solid suspended in gas
[B] Liquid suspended in gas
[C] Gas suspended in liquid
[D] Gas suspended in solid
Show Answer
Correct Answer: C [Gas suspended in liquid]
Notes:
Froth and foams are examples of “gas suspended in liquid”. They are typically created when gas bubbles are dispersed in a liquid. This physical phenomenon is commonly observed in many daily life scenarios such as soap lather and carbonated drinks. Technically, they are a special case of colloid where little blobs of one liquid are dispersed in another and show the property of surface tension.
5. The chemical oxygen demand COD test is commonly used to measure which of the following?
[A] amount of organic compounds in water
[B] amount of oxygen in water
[C] amount of oxygen in a chemical
[D] amount of oxygen used in a oxygenation process
Show Answer
Correct Answer: A [amount of organic compounds in water]
Notes:
chemical oxygen demand is a measure of water quality and is amount of organic pollutants found in surface water. Potassium permanganate has been used for many years to measure COD
6. Argon is the third most common gas in the Earth’s atmosphere, at 0.93%. This gas is generated due to decay of which among the following isotopes in the Earth’s crust ?
[A] K-40
[B] Ca-40
[C] Ca-48
[D] K-41
Show Answer
Correct Answer: A [K-40]
Notes:
Potassium-40 is a radioactive isotope of potassium with a long half-life of 1.251×10⁹ years. The decay of this particular isotope explains the large abundance of argon (0.93%) in the Earth’s atmosphere.
7. Plumbism is a condition which occurs due to accumulation of:
[A] Lead in the body
[B] Sodium in the body
[C] Cadmium in the body
[D] Potassium in the body
Show Answer
Correct Answer: A [ Lead in the body]
Notes:
Plumbism is also known as lead poisoning or a condition which occurs when there is accumulation of lead in body, usually over a few months' time period and even years.
8. Which of the following is the softest metal?
[A] Cesium
[B] Lead
[C] Gold
[D] Silver
Show Answer
Correct Answer: A [ Cesium]
Notes:
Cesium is extremely reactive metal. It reacts with water even at −116 °C (−177 °F). It is the least electronegative element. Cesium is also the softest known metal. It is so soft that it can be cut with a butter knife.
9. Which of the following chemicals is also known as "sweet oil of vitriol"?
[A] Diethyl ether
[B] Aluminium sulphate
[C] Sulphuric acid
[D] Iron(III) sulphate
Show Answer
Correct Answer: A [ Diethyl ether]
Notes:
Diethyl ether is a colourless, highly volatile & flammable organic compound. It was earlier used for anaesthesia but after the development of non-flammable drugs, its uses as anaesthetic has been reduced.
10. Which of the following compounds is manufactured using the Contact Process?
[A] Sulphuric Acid
[B] Nitric Acid
[C] Hydrochloric Acid
[D] Benzene
Show Answer
Correct Answer: A [Sulphuric Acid]
Notes:
The Contact Process is a method primarily used for preparing sulphuric acid on a large scale. It involves the oxidation of sulfur dioxide to sulfur trioxide in presence of a catalyst such as vanadium pentoxide. The subsequent hydration of sulfur trioxide produces sulphuric acid. The Contact Process allows the production of high concentrations of sulphuric acid under economically feasible conditions.
