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 among the following elements are generally find in free state?
[A] Group 11 elements
[B] Group 12 elements
[C] Group 13 elements
[D] Group 14 elements
Show Answer
Correct Answer: A [Group 11 elements ]
Notes:Group 11 is also known as the coinage metals, due to their former usage. They were most likely the first three elements discovered. Copper, silver, and gold all occur naturally in elemental form.
2. Which among the following is major component of Gobar Gas?
[A] Butane
[B] Ethane
[C] Propane
[D] Metahne
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Correct Answer: D [Metahne]
Notes:
Gobar Gas or Biogas is mostly methane (CH4) and carbon dioxide (CO2) and may have small amounts of hydrogen sulfide (H2S), moisture and siloxanes.
3. Which among the following is the most abundant organic compound in nature?
[A] Glucose
[B] Fructose
[C] Sucrose
[D] Cellulose
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Correct Answer: D [Cellulose]
Notes:
Cellulose is the most abundant organic compound in nature. It is the main constituent of plant fiber. Plants contain on average 33% cellulose, and cotton is the purest form at 90%. Chitin is the second most abundant organic compound in nature.
4. Which of the following alkali metal ions has the highest hydration enthalpy?
[A] Lithium
[B] Sodium
[C] Potassium
[D] Caesium
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Correct Answer: A [Lithium]
Notes:
Lithium ions has maximum degree of hydration and for this reason lithium salts are mostly hydrated.
5. Which of the following alkaline earth metals is the rarest in the earth crust?
[A] Calcium
[B] Strontium
[C] Radium
[D] Beryllium
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Correct Answer: C [Radium]
Notes:
Of the alkaline earth metals calcium and magnesium rank fifth and sixth in abundance respectively in the earth’s crust. Strontium and barium have much lower abundances. Beryllium is rare and radium is the rarest of all comprising only 10–10 per cent of igneous rocks.
6. Which of these industrial processes is used for production of aluminium from alumina?
[A] Vunyukov process
[B] Hall–Heroult process
[C] Betts process
[D] None of the above
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Correct Answer: B [Hall–Heroult process]
Notes:
The Hall–Heroult process is the major industrial process for production of aluminium. It involves dissolving aluminium oxide in molten cryolite and electrolysing the molten salt bath to get pure aluminium.
7. What is the half-life of Radium-223 isotope?
[A] 3 days
[B] 5 days
[C] 11.4 days
[D] 9.5 days
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Correct Answer: C [11.4 days]
Notes:
The half-life of Radium-223 isotope is 11.4 days. The radium-226, which is a more common isotope of Radium and which wad discovered by the Curies, has a 1601-year half-life.
8. How many periods and groups are there in the Modern Periodic table?
[A] 18 groups, 7 periods
[B] 16 groups, 18 periods
[C] 7 groups, 18 periods
[D] 14 groups, 8 periods
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Correct Answer: A [18 groups, 7 periods]
Notes:
The Modern Periodic Table has 18 vertical columns known as ‘groups’ and 7 horizontal rows known as ‘periods’.
9. The Lanthanoids are part of which of the following block of elements in the periodic table?
[A] p-block
[B] s-block
[C] d-block
[D] f-block
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Correct Answer: D [f-block]
Notes:
Lanthanoids form part of the series of chemical elements comprising the 15 metallic chemical elements with atomic numbers 57 through 71, from lanthanum through lutetium. They are a part of f-block of elements in the periodic table
10. What is the PH of human blood?
[A] 8.2
[B] 7.4
[C] 6.5
[D] 7
Show Answer
Correct Answer: B [7.4]
Notes:
Blood is normally slightly basic, with a normal pH range of 7.35 to 7.45. Usually the human body maintains the pH of blood close to 7.40.
