Chemistry MCQs
Chemistry Objective (Multiple Choice) General Knowledge Questions & Answers for SSC-CGL, UPPSC, UPSC, NDA, CDS and UPSC Civil Services Prelims Examination.
1. A cotton wick dipped in pure honey when ignited with a matchstick will ______?
[A] Burn steadily
[B] Burn with a cracking sound
[C] Not burn at all
[D] Burn producing a large amount of smoke
Show Answer
Correct Answer: A [Burn steadily]
Notes:
A cotton wick soaked in pure honey, when lit with a matchstick, will burn consistently. This is primarily due to the high sugar content of the honey acting as fuel for the flame. Contrary to common misconceptions, honey doesn’t produce much smoke or any unusual sounds during combustion.
2. Which of the following type of Coal has maximum carbon content?
[A] Peat
[B] Lignite
[C] Antharacite
[D] Bituminious
Show Answer
Correct Answer: C [Antharacite]
Notes:
Anthracite, often referred to as hard coal, is a hard, compact variety of coal that has a submetallic luster. It has the highest carbon content, the fewest impurities, and the highest energy density of all types of coal and is the highest ranking of coals.
3. Galena & Litharge are ores of which of the following metals?
[A] Mercury
[B] Zinc
[C] Copper
[D] Lead
Show Answer
Correct Answer: D [Lead]
Notes:
Galena and litharge are ores of lead. Galena is the most common ore of lead. It is the natural mineral form of lead (II) sulphid. Litharge is a secondary mineral that forms from the oxidation of galena ores. It is one of the natural mineral forms of Lead(II) oxide.
4. 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.
5. What characteristic of silica gel, a granular form of silica produced from sodium silicate, enables it to control humidity and prevent spoilage or degradation when packaged with various products?
[A] Its high thermal conductivity
[B] Its hygroscopic properties
[C] Its high reflectivity
[D] Its low thermal conductivity
Show Answer
Correct Answer: B [Its hygroscopic properties]
Notes:
Silica gel possesses hygroscopic properties, meaning it can absorb and hold water vapour. This makes it an effective desiccant or drying agent. When packaged with products, silica gel can help control humidity and prevent spoilage or degradation by absorbing excess moisture. This property is particularly valuable when shipping or storing items that can be negatively impacted by damp conditions, like electronics, food, and leather goods.
6. Which of the following are two predominant acids of acid rain?
[A] sulphuric acid and nitric acid
[B] carbonic acid and hydrochloric acid
[C] nitric acid and hydrochloric Acid
[D] hydrofluoric acid and hydrochloric Acid
Show Answer
Correct Answer: A [ sulphuric acid and nitric acid ]
Notes:
Acid rain, or acid deposition, is a broad term that includes any form of precipitation with acidic components, such as sulphuric or nitric acid that fall to the ground from the atmosphere in wet or dry forms.
7. Which among the following impurity in drinking water causes the “Bamboo Spine” disorder?
[A] Nitrate
[B] Fluorides
[C] Arsenic
[D] Sulphides
Show Answer
Correct Answer: B [ Fluorides]
Notes:
Ankylosing Spondylitis is a chronic, inflammatory arthritis and autoimmune disease that mainly affects joints in the spine and the sacroiliac joints in the pelvis. It tends to affect the spine and in late stages, the spine will fuse and this has given rise to the term “bamboo spine”. It is mainly caused due to impurities in drinking water associated with fluorides.
8. Consider the following:
- Hydrogen (H2)
- Carbon monoxide (CO)
- Carbon dioxide (CO2)
- Methane (CH4)
Which of the above is/are component(s) of high-quality (100% pure) Syngas?
[A] 1 Only
[B] 1 & 2 Only
[C] 1, 2 & 3 Only
[D] 1, 2, 3 & 4
Show Answer
Correct Answer: B [ 1 & 2 Only]
Notes:
The high-quality (100% Pure) Syngas has the main components of (H2 + CO)
9. What is the general trend for ionization enthalpies of alkali metals as we move down the group?
[A] it increases
[B] it decreases
[C] it is same for all
[D] None
Show Answer
Correct Answer: B [it decreases]
Notes:
The ionization enthalpies of the alkali metals are considerably low and decrease down the group from Li to Cs.
10. Which of the following metal is alloyed with pure gold to make gold ornaments?
[A] Silver
[B] Copper
[C] Zinc
[D] All of the above
Show Answer
Correct Answer: D [All of the above]
Notes:
24 carat gold is considered to be the purest form of gold but it is too soft to be made into jewellery. It is alloyed with metals like zinc, cadmium, silver or copper to make it hard.
