General Science Chemistry MCQs
Chemistry Objective (Multiple Choice) General Knowledge Questions & Answers for SSC-CGL, UPPSC, UPSC, NDA, CDS and UPSC Civil Services Prelims Examination
41. Which of the following represents the general formula for alkanes?
[A] CnH2n
[B] CnH2n-2
[C] CnH2n+2
[D] CnHn
Show Answer
Correct Answer: C [CnH2n+2]
Notes:
Alkanes are saturated open chain hydrocarbons containing carbon – carbon single bonds.
42. Which of the following is correct about Hydrazine?
[A] It is used in various rocket fuels
[B] Is chemical formula is N2 H2
[C] It is a blue colour liquid
[D] All of the above
Show Answer
Correct Answer: A [It is used in various rocket fuels]
Notes:
The chemical formula of Hydrazine is N2 H4. it is a colorless flammable liquid with an ammonia-like odour. It is used in various rocket fuels.
43. Which of the following is NOT correct about Phosphine?
[A] The chemical formula is PH3
[B] The electronic structure is like Ammonia
[C] It is odorless
[D] it is used as a dopant in semiconductor industries
Show Answer
Correct Answer: C [It is odorless]
Notes:
Phosphine is PH3. The electronic structure of Phosphine (pyramidal structure) is like Ammonia. It is a colourless gas and has a spoiled fish smell. It is used as a dopant in semiconductor industries.
44. Which of the following is correct about ozone?
[A] it is a red coloured gas
[B] it is odourless
[C] it is harmless in small concentrations
[D] All of the above
Show Answer
Correct Answer: C [it is harmless in small concentrations]
Notes:
Pure ozone is a pale blue gas, dark blue liquid and violet-black solid. Ozone has a characteristic smell and in small concentrations it is harmless. However, if the concentration rises above about 100 parts per million, breathing becomes uncomfortable resulting in headache and nausea.
45. Which of the following compounds is prepared using Contact Process?
[A] Sulphuric Acid
[B] Nitric Acid
[C] Hydrochloric Acid
[D] Benzene
Show Answer
Correct Answer: A [Sulphuric Acid]
Notes:
Sulphuric acid is manufactured by the Contact Process. Its chemical formula is H2 SO4.
46. Which of the following is correct about HCl gas?
[A] It is a colourless and pungent smelling gas
[B] It is extremely soluble in water
[C] Both a and b
[D] None
Show Answer
Correct Answer: C [Both a and b]
Notes:
It is a colourless and pungent smelling gas. It is easily liquefied to a colourless liquid and freezes to a white crystalline solid . It is extremely soluble in water.
47. Which of these is NOT a compound of carbon?
[A] Acetic acid
[B] Chloroform
[C] Caustic Soda
[D] Methane
Show Answer
Correct Answer: C [Caustic Soda]
Notes:
Caustic soda is a compound of sodium where as Acetic acid, Chloroform and Methane are the compounds of carbon.
48. Which of the following defines the solubility of a solution?
[A] amount of the solvent present in the saturated solution
[B] amount of the solute present in the saturated solution
[C] amount of the solute per amount of solute in the solution
[D] difference of amount of solvent and the amount of solute
Show Answer
Correct Answer: B [amount of the solute present in the saturated solution]
Notes:
The amount of the solute present in the saturated solution at a given temperature is called its solubility.
49. Which of the following is not the correct way of expressing the concentration of a solution?
[A] (Mass of solute/Mass of solution) x 100
[B] (Volume of solute/Volume of solution) x 100
[C] (Mass of solute/Volume of solution) x 100
[D] (Volume of solvent/Volume of solution) x 100
Show Answer
Correct Answer: D [(Volume of solvent/Volume of solution) x 100]
Notes:
The concentration of a solution is the amount (mass or volume) of solute present in a given amount (mass or volume) of solution.
50. Which of the following is correct about suspension?
[A] It is a heterogeneous mixture
[B] The particles of a suspension can be seen by naked eyes
[C] The particles can be separated from the mixture by the process of filtration
[D] All of the above
Show Answer
Correct Answer: D [All of the above]
Notes:
Suspension is a heterogeneous mixture. The particles of a suspension can be seen by the naked eye. The solute particles can be separated from the mixture by the process of filtration.
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