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 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.
42. 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.
43. Which of the following is not a mixture?
[A] Ocean water
[B] Table salt
[C] Air
[D] Soil
Show Answer
Correct Answer: B [Table salt]
Notes:
The composition of a mixture is variable whereas it is fixed for a compound. Table salt i.e. Sodium chloride is a compound and not a mixture.
44. 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.
45. 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.
46. Which of the following techniques can be used to separate cream from milk?
[A] Filtration
[B] Distillation
[C] Centrifugation
[D] Chromatography
Show Answer
Correct Answer: C [Centrifugation]
Notes:
Centrifugation is a mechanical process that utilizes an applied centrifugal force field to separate the components of a mixture.
47. Which method will is most suitable to separate the mixture of ammonium chloride and salt?
[A] Evaporation
[B] Sublimation
[C] Simple Distillation
[D] All of the above
Show Answer
Correct Answer: B [Sublimation]
Notes:
Sublimation is the property of substance in which they are converted directly from solid to gas or vice versa. Ammonium chloride is a sublime solid.
48. What is an alloy of mercury with some other metal generally known as?
[A] Galinston
[B] Amalgam
[C] Megalium
[D] Yellow metal
Show Answer
Correct Answer: B [Amalgam]
Notes:
Amalgam is the general name given to an alloy of mercury with some other metal. It can be a solid, liquid or a soft paste depending on the composition of the constituents.
49. 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.
50. Which of the following is / are correct statements about Roasting?
- In Roasting, the ore is heated in a regular supply of air
- Roasting is used to convert the concentrated ore to oxide
- Roasting is commonly used for sulphide ores
Select the correct option from the codes given below:
[A] Only 1 & 2
[B] Only 2 & 3
[C] Only 1 & 3
[D] 1, 2 & 3
Show Answer
Correct Answer: D [1, 2 & 3]
Notes:
Roasting is the process of converting an ore into its oxide by heating the ore in regular supply of oxygen. It is commonly used for suiphide ores.
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