Chemistry MCQs
Chemistry Objective (Multiple Choice) General Knowledge Questions & Answers for SSC-CGL, UPPSC, UPSC, NDA, CDS and UPSC Civil Services Prelims Examination.
1. 2,4-D, which is sold as a weed killer of the broad-leaved weeds is a synthetic version of __:
[A] Auxin Hormone
[B] Cytokinin Hormone
[C] Xylitol
[D] None of them
Show Answer
Correct Answer: A [Auxin Hormone ]
Notes:
2,4-dichlorophenoxyacetic acid (2,4-dichlorophenoxyethanoic acid) is a synthetic auxin frequently used as a weed killer of broad-leaved weeds. When two herbicides 2,4,5-T and 2,4-D and mixed in equal parts, it is called Agent Orange, which was used by US in Vietnam war.
2. Which of the following compound of sodium is generally prepared by Solvay process?
[A] Sodium Carbonate
[B] Sodium Hydroxide
[C] Sodium Chloride
[D] All of the above
Show Answer
Correct Answer: A [Sodium Carbonate]
Notes:
Sodium carbonate is generally prepared by Solvay Process.
3. Which of the following is correct?
[A] A colloidal solution is a heterogeneous mixture
[B] A colloidal solution is a homogeneous mixture
[C] The particles of a colloidal solution cannot scatter beam of light
[D] None of the above
Show Answer
Correct Answer: A [A colloidal solution is a heterogeneous mixture]
Notes:
Due to the relatively smaller size of particles, as compared to that of a suspension, the mixture appears to be homogeneous. But actually, a colloidal solution is a heterogeneous mixture. The particles can easily scatter a beam of visible light.
4. Which of the following is correct about Solder?
[A] It is an alloy of lead and tin
[B] It is used for welding electrical wires together
[C] It has a low melting point
[D] All of the above
Show Answer
Correct Answer: D [All of the above]
Notes:
Solder is an alloy of lead and tin (Pb and Sn). It has a low melting point and is used for welding electrical wires together.
5. Choose the incorrect statement:
[A] Epsom salt is an ore containing Sodium
[B] Bauxite is an ore of Aluminium
[C] Asbestos is an ore containing Calcium
[D] Milarite mineral contains Nickel
Show Answer
Correct Answer: A [Epsom salt is an ore containing Sodium]
Notes:
Epsom salt is an ore containing Magnesium. It is also known as the heptahydrate sulfate mineral. Its chemical formula is MgSO4·7H2O.
6. Which of the following reactions take place when iron nail in a copper sulphate solution becomes brownish in colour?
[A] Decomposition reaction
[B] Displacement reaction
[C] Double Displacement reaction
[D] None of the above
Show Answer
Correct Answer: B [Displacement reaction]
Notes:
Iron nail in the Copper Sulphate solution become brownish in colour and the blue colour of copper sulphate solution fade. This happens because iron has displaced or removed another element, copper, from copper sulphate solution. This reaction is known as displacement reaction.
7. Which of the following group of elements contain the noble gases?
[A] s-block
[B] p-block
[C] d-block
[D] f-block
Show Answer
Correct Answer: B [p-block]
Notes:
The p-Block Elements comprise those belonging to Group 13 to 18 and these together with the s-Block Elements are called the Representative Elements or Main Group Elements. The 18th group i.e. the last group of the p-block elements is the noble gases group.
8. Which of the following elements has the largest atomic radii?
[A] Lithium
[B] Beryllium
[C] Boron
[D] Carbon
Show Answer
Correct Answer: A [Lithium]
Notes:
The atomic radius generally decreases across a period. Therefore, Lithium will have the largest atomic radii among the given elements as it is placed before others as we move from left to right in the periodic table.
9. What is the product when Methane reacts with steam in the presence of Nickel catalyst?
[A] Carbon dioxide and ethane
[B] Ethyne
[C] Carbon monoxide and dihydrogen
[D] Carbon monoxide and Water vapour
Show Answer
Correct Answer: C [Carbon monoxide and dihydrogen]
Notes:
Methane reacts with steam at 1he temperature of 273 K in the presence of nickel catalyst to form carbon monoxide and dihydrogen. This method is used for industrial preparation of dihydrogen gas.
10. Which of these fuels is a hydrocarbon or mixture of hydrocarbons?
[A] LPG
[B] CNG
[C] Petrol
[D] All of the above
Show Answer
Correct Answer: D [All of the above]
Notes:
Hydrocarbons are those compounds which contains Hydrogen and carbon. Some of the important hydrocarbon fuels are LPG, CNG, Petrol, Coal gas etc.
