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. These questions are part of GKToday’s 35000+ MCQs Bank Course in GKToday Android App
31. Iron filings can be separated from a heterogenous mixture using the technique of:
[A] Sublimation
[B] Magnetization
[C] Sedimentation
[D] Evaporation
Show Answer
Correct Answer: B [Magnetization]
Notes:
The method of separation using magnets is used when one of the components is magnetic. So the heterogeneous mixture of iron filings and some other material (such as sulphur powder) can be separated by using magnets. Similarly, a mixture of sand and iron filings can be separated by magnet.
32. The strongest oxidizing agent among the following is:
[A] Chlorine
[B] Iodine
[C] Fluorine
[D] Oxygen
Show Answer
Correct Answer: C [Fluorine]
Notes:
An oxidizing agent is a chemical species that removes an electron from another species. Fluorine, having the largest positive value of electrode potential, is the strongest oxidizing agent.
33. Which among the following will be a negative ion?
[A] If it has more electrons than protons
[B] If it has more electrons than neutrons
[C] If it has more protons than electrons
[D] If it has more protons than neutrons
Show Answer
Correct Answer: A [If it has more electrons than protons]
Notes:
When an atom is attracted to another atom because it has an unequal number of electrons and protons, the atom is called an ion. If the atom has more electrons than protons, it is a negative ion, or Anion. If it has more protons than electrons, it is a positive ion (cation).
34. Soda water has a pH value ______:
Show Answer
Correct Answer: B [<7]
Notes:
The pH level of carbonated water ranges between 3 and 4, where a pH of 7 is neutral, a pH of 14 is highly basic, and a pH of 0 is highly acidic.
35. Heating of rubber with Sulphur is known as _____:
[A] Galvanisation
[B] Sulphonation
[C] Bessemerisation
[D] Vulcanisation
Show Answer
Correct Answer: D [Vulcanisation]
Notes:
Sulfur vulcanization or sulfur vulcanisation is a chemical process for converting natural rubber or related polymers into more durable materials by heating them with sulphur, or other equivalent curatives or accelerators.
36. A battery converts which energy to electrical energy?
[A] mechanical
[B] chemical
[C] light
[D] heat
Show Answer
Correct Answer: B [chemical]
Notes:
A battery is a device that is able to store electrical energy in the form of chemical energy, and convert that energy into electricity.
37. Which one out of the following helps in burning?
[A] Oxygen
[B] Carbon monoxide
[C] Nitrogen
[D] Carbon dioxide
Show Answer
Correct Answer: A [Oxygen]
Notes:
Joseph Priestley, the English chemist, also prepared oxygen in 1774 by focusing the sun’s rays with the help of a lens on mercuric oxide. Its elemental nature was, however, established by the French chemist, Lavoisier proving its necessity in burning.
38. Which of the following is not a greenhouse gas?
[A] Water vapour
[B] O2
[C] O3
[D] CO2
Show Answer
Correct Answer: B [O2]
Notes:
Greenhouse gases are those that can absorb and emit infrared radiation, but not radiation in or near the visible spectrum. The most abundant greenhouse gases in Earth’s atmosphere are: Water vapor (H2O), Carbon dioxide (CO2), Methane (CH4), Nitrous oxide (N2O), Ozone (O3) and CFCs.
39. The most abundant metal in the Earth’s crust is:
[A] zinc
[B] copper
[C] aluminium
[D] iron
Show Answer
Correct Answer: C [aluminium]
Notes:
The most abundant metal on Earth is aluminum. Aluminum is the third most abundant element in the Earth’s crust, and makes up 8 percent of it by parts per million. The most abundant element in the Earth’s crust is Oxygen followed by Silicon but both of these are non-metals.
40. Which one of the following non-metals shows allotropy in the liquid state?
[A] Carbon
[B] Sulphur
[C] Phosphorous
[D] Bromine
Show Answer
Correct Answer: B [Sulphur]
Notes:
Sulphur is a non-metal that shows allotropy in the liquid state. If sulphur is heated slowly the changes between the different forms can be observed. These changes are in the form of colour and viscosity (thickness) of the liquid. If the dark brown liquid sulphur is poured into a beaker of cold water, plastic sulphur is formed. This is an elastic, rubber-like form of sulphur. The tow commonly know allotropic forms of sulphur are monoclinic and rhombhic sulphur.
