lecturer chemistry important mcqs

  Most Important mcqs For Lecturer Chemistry 

 

Chemistry mcqs For All Exams

 

 

 

1. Smallest particle of an element which may or may not have independent existence :





ANSWER= (B) An atom

 

2. Swedish chemist J. Berzelius determined the :





ANSWER= (C) Atomic mass

 

3. The numbers of atom present in a molecule determine its:





ANSWER= (D) Atomicity

 

4. When an electron is added to a uni positive ion we get:





ANSWER= (C) Neutral atom

 

5. CO+ is an example of :





ANSWER= (B) Cationic molecular ion

 

6. Relative atomic mass is the mass of an atom of an element as compared to the mass of:





ANSWER= (D) Carbon

 

7. Isotopes are the sister atoms of the same element with similar chemical properties and different :





ANSWER= (B) Atomic mass

 

8. The instrument which is used to measure the exact masses of different isotopes of an element is called:





ANSWER= (C) Mass spectrometer

 

9. Mass spectrometer separates different positive isotopic ions on the basis of their :





ANSWER= (B) m/e value

 

10. Simplest formula that gives us information about the simple ratios of atoms in a compound is called :





ANSWER= (C) Empirical formula

 

11. Percentage of oxygen in H2O is:





ANSWER= (B) 88.8%

 

12. More abundant isotope of an element is one with :





ANSWER= (C) Even mass number

 

13. Large number of isotopes are known for the elements whose masses are multiple of:





ANSWER= (B) Four

 

14. When 0.01kg of CaCO3 is decomposed the CO2 produced occupies the volume at S. T. P. :





ANSWER= (A) 2.2414 dm3

 

15. The number of covalent bond in 10 gm of NH3 are:





ANSWER= (D) 1.062×10²⁴

 

16. Number of molecules present in 10gm of water are :





ANSWER= (A) 3.37×10²³

 

17. The number of covalent bonds in 10 gm of water are:





ANSWER= (B) 6.74×10²³

 

18. The least number of molecules present in 30 gm of:





ANSWER= (D) N2O3

 

19. Which of the following has highest percentage of nitrogen :





ANSWER= (D) (NH4)3PO4

 

20. 0.1 mole of Na3PO4 completely dissociates in water to produce Na+:





ANSWER= (C) 1.806×10²³

 

21. Efficiency of chemical reaction can be checked by calculating :





ANSWER= (C) Amount of the product formed

 

22. A limiting reactant is one :





ANSWER= (B) Which produces minimum number of moles of product

 

23. Stoichiometery is the branch of chemistry which deals with the study of quantitative relationship among the various :





ANSWER= (D) All of these

 

24. 500 cm3 of H2 gass at STP contradiction of hydrogen :





ANSWER= (C) 2.68×10²²

 

25. Largest number of H+ ions are produced by complete ionization of:





ANSWER= (D) All of these

 

26. The Avogadro's number is :





ANSWER= (D) 6.02×10²³

 

27. A sample of pure matter is :





ANSWER= (A) Element

 

28. nm stands for:





ANSWER= (B) Nanometer

 

29. One calorie is equal to :





ANSWER= (A) 4.184 J

 

30. The number of moles of CO2 which contains 8.0 gm of oxygen :





ANSWER= (A) 0.25

 

31. 27 grams of aluminium will react completely with how much mass of O2 to produce Al2O3:





ANSWER= (D) 24 gm of oxygen

 

32. Moles of SO2 contains :





ANSWER= (C) 6.023×10²³ atoms of sulphur

 

33. A molecule having two atoms is called :





ANSWER= (C) Polyatomic molecule

 

34. An ordinary microscope is used to measure the object of size:





ANSWER= (A) Upto 500 nm

 

35. Nickle has isotopes :





ANSWER= (C) 5

 

36. Cadmium has isotopes :





ANSWER= (D) 9

 

37. The pressure of vapours in the separating isotopes by mass spectrometry is kept at:





ANSWER= (A) 10-6 torr

 

38. Number of gram atom in 0.1 gm of Na is:





ANSWER= (A) 0.0043

 

39. Molecule of haemoglobin contains atoms:





ANSWER= (C) 10,000

 

40. Haemoglobin is heavier than a hydrogen atom:





ANSWER= (B) 68,000

 

41. Science of the chemical characterization is stand under the heading of:





ANSWER= (C) Analytical chemistry

 

42. Several types of filter media are used for filtration depending on :





ANSWER= (C) Nature of precipitate

 

43. Date of filtration through conical funnel can be considerably increased by using :





ANSWER= (C) Fluted paper

 

44. Repeated extraction using small portion of solvents are more:





ANSWER= (B) Efficient

 

45. To achieve a good separation the two liquids are gently shaken to increase their area of:





ANSWER= (C) Contact

 

46. In paper chromatography the mobile phase is :





ANSWER= (A) Organic liquid

 

47. In paper chromatography the stationary phase is :





ANSWER= (A) Water

 

48. Which is not common way of carrying chromatography :





ANSWER= (D) Spreading irregularly

 

49. The meaning of chromatos:





ANSWER= (A) Colour writing

 

50. Safe and reliable method of drying crystal in through :





ANSWER= (D) Vacuum desiccant

 

 

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