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 also known as wood alcohol?
[A] Methanol
[B] Ethanol
[C] Propanal
[D] Butanol
Show Answer
Correct Answer: A [Methanol]
Notes:
Methanol (CH3OH) is also known as Wood Alcohol. It’s a solvent in many chemical processes and is a component of automobile antifreeze.
2. Which of the following is not a non-metallic mineral?
[A] Mica
[B] Bauxite
[C] Granite
[D] Silica
Show Answer
Correct Answer: B [Bauxite]
Notes:
Non-metallic minerals are those minerals which do not contain metals. Examples of Non-Metallic minerals include limestone, mica, coal, gypsum, dolomite, phosphate, salt, granite etc.
3. The aqueous solution of which among the following acids is called Vinegar?
[A] Oxalic acid
[B] Citric acid
[C] Acetic acid
[D] Hydrochloric acid
Show Answer
Correct Answer: C [Acetic acid ]
Notes:
Acetic acid (CH3COOH) is a weak organic acid that gives vinegar its sour taste. At household concentrations (5-8% acetic acid), it is a mild acid. Vinegar can be made from a variety of base ingredients including wine, apple cider, rice, or malt. The acetic acid is produced by fermentation of the sugars in these ingredients. The most common type of vinegar in households is white distilled vinegar which is typically 4-7% acetic acid. It has a strong, pungent smell and flavor.
4. Which among the following gases is used in production of Vanaspati ghee from vegetable oils?
[A] Nitrogen (N2)
[B] Carbon Dioxide (CO2)
[C] Hydrogen (H2)
[D] Neon (Ne)
Show Answer
Correct Answer: C [Hydrogen (H2)]
Notes:
Hydrogen (H2) gas is utilized in the manufacture of Vanaspati ghee from vegetable oils. The process involves hydrogenation, a chemical reaction between molecular hydrogen (H2) and another compound or element. Hydrogenation of vegetable oils helps to convert them into a semisolid form that resembles ghee, often used as a cheaper alternative to butter or ghee in cooking.
5. When a piece of quicklime is dipped in water, it gives bubbles. This bubbling is due to which of the following ?
[A] Oxygen
[B] Carbon Dioxide
[C] Water Vapour
[D] Hydrogen
Show Answer
Correct Answer: C [Water Vapour]
Notes:
When quicklime (calcium oxide) is added to water, it reacts exothermically to form calcium hydroxide (slaked lime). This reaction produces heat and releases water vapor, which causes bubbling. The reaction can be represented as: [ ext{CaO} + ext{H}_2 ext{O}
ightarrow ext{Ca(OH)}_2 + ext{heat} ] Trivia: Quicklime is used in various applications, including steelmaking and water treatment, and was historically used in ancient construction.
6. Which among the following kinds of Chemical reactions cause the rocks turn red or yellowish?
[A] Hydration
[B] Oxidation
[C] Carbonation
[D] Exfoliation
Show Answer
Correct Answer: B [Oxidation]
Notes:
The correct answer is Oxidation. This reaction occurs when minerals in rocks, particularly iron-bearing minerals, react with oxygen. This process can lead to the formation of iron oxides, which give rocks a reddish or yellowish hue. For example, rusting of iron in rocks is a common oxidation reaction. Oxidation is a important weathering process, contributing to soil formation and landscape changes.
7. Which among the following compound is most commonly used in the Photochromic lenses?
[A] Potassium Dichromate
[B] Silver Chloride
[C] Potassium ferrate
[D] Ferric Chloride
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Correct Answer: B [ Silver Chloride]
Notes:
Silver halides and most commonly silver Chloride is used in Photochromic lens. But for plastic photochromic lenses, some organic products such as oxazines and naphthopyrans are used.
8. The vegetable oil treated with which among the following halogens makes it an additive, which is used in artificial citrus flavoured aerated drinks to give it the cloudy look, so that consumers get deceived because it appears natural citrus drink?
[A] Chlorine
[B] Bromine
[C] Iodine
[D] Fluorine
Show Answer
Correct Answer: B [ Bromine]
Notes:
Brominated Vegetable Oil is an additive, which is used in artificial citrus flavoured aerated drinks to give it the cloudy look, so that consumers are fooled into believing that it is the real thing. India banned BVO in 1988. It is used in some countries.
9. Which of the following laws is used as a rule to predict the solubility of gases in metals?
[A] Dalton’s Law
[B] Sievert’s law
[C] Graham’s law
[D] Henry’s law
Show Answer
Correct Answer: B [ Sievert’s law]
Notes:
Sievert’s law is used as a rule in physical metallurgy to predict the solubility of gases in metals.
10. The presence of which of the following chemical elements helps to differentiate between sweet and sour crude oil?
[A] Iron
[B] Sulphur
[C] Vanadium
[D] Chromium
Show Answer
Correct Answer: B [ Sulphur ]
Notes:
Crude oil with high amount of Sulphur is termed as sour and with less Sulphur is called the sweet grade. Sour grade crude requires extra processing cost.