Chemistry Questions and Answers – Basic Chemistry

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100 Chemistry Questions and Answers – Basic Chemistry

 

Chemistry Questions and Answers - Basic Chemistry

 

Chemistry Questions – Learn Basic Chemistry Part 1 (1-25)

 

1) When a beam of white rays is dispersed by a prism which colour will be refracted to a larger extent?

Answer: Violet.

 

2) The modern atomic mass unit is based on ____
Answer: Carbon-12.

 

3) What do you mean by photoelectric effect?

Answer: Emission of electrons by electromagnetic radiation striking on a metal surface.

 

4) A raincoat is made of what?

Answer: Polychloroethene.

 

5) What is the value of Planck’s constant in SI units?

Answer: 6.625 x 10’34 Is.

 

6) The total number of electrons present in 18 ml of water is ____

Answer: 6.02 × 1024.

 

7) What is the velocity of light in m/s?

Answer: 3 x 108 m/s.

 

8) Which element on adding to natural rubber makes it less sticky in hot weather and less hard in cold weather?

Answer: Sulfur.

 

9) The scientist who introduced the model of the atom similar to the solar system?

Answer: Ernest Rutherford.

 

10) 3 g of a salt of molecular weight 30 is dissolved in 250 g of water. The molality of the solution is ____

Answer: 0.4m.

 

11) What happens when an electron moves nearer to the nucleus of the atom?

Answer: Its energy decreases.

 

12) Which chemical causes Minamata disease?

Answer: Mercury.

 

13) What is molarity?

Answer: Number of moles of solute in one liter of the solution.

 

14) The weight of 1 × 1022 molecules of CuSO4 .5H2O is ____
Answer: 4.14 g.

 

15) What kind of thermometer is used to determine the depression of freezing point?

Answer: Beckmann thermometer.

 

16) The absence of cobalt in minute quantities in human body causes what?

Answer: Pernicious anemia.

 

17) What do you mean by a buffer solution?

Answer: Solution which can maintain constant PH.

 

18) 27 g of Al will react completely with how many grams of oxygen?
(a) 8 g (b) 16 g (c) 32 g (d) 24 g
Answer: D.

 

19) Which element has no neutrons in it?

Answer: Hydrogen.

 

20) Which element can easily form chains?

Answer: Carbon.

 

21) What is the fundamental particle present in P – rays?

Answer: Electron.

 

22) A compound was found to contain nitrogen and oxygen in the ratio 28 gm and 80 gm respectively. The formula of the compound is
(a) NO (b) N2O3 (c) N2O5 (d) N2O4
Answer: C.

 

23) Give the name of the radioactive isotope of hydrogen:

Answer: Tritium.

 

24) Cement mixed with gravel, sand, and water is called what?

Answer: Concrete.

 

25) What are isotopes?

Answer: Atoms having the same atomic number but a different mass number.

 

Online Chemistry Questions and Answers – Basic Chemistry Part 2 (26-50)

 

26) The largest number of molecules is in
(a) 36 g of water (b) 28 g of carbon monoxide (c) 46 g of ethyl alcohol (d) 54 g of nitrogen pentoxide
Answer: A.

 

27) What are isobars?

Answer: Same mass number but a different atomic number.

 

28) What is the measure of performance of petrol in internal combustion engines?

Answer: Octane number.

 

29) What is Isotone?

Answer: Atoms having an equal number of neutrons.

 

30) The total number of electrons in one molecule of carbon dioxide is
(a) 22 (b) 44 (c) 66 (d) 88
Answer: A.

 

31) What do you mean by dating of objects?

Answer: Determination of age.

 

32) Glass is made out of what?

Answer: Sand.

 

33) Name any two nuclei used to make an atom bomb:

Answer: Uranium, Plutonium.

 

34) A gaseous mixture contains oxygen and nitrogen in the ratio of 1: 4 by weight. Therefore the ratio of their number of molecules is
(a) 1: 4 (b) 1: 8 (c) 7: 32 (d) 3: 16
Answer: C.

 

35) What is the half-life of 6C14?

Answer: 5760 years.

 

36) Which is considered to be an anomalous compound?

Answer: Water.

 

37) Bronze is an alloy of what?

Answer: Tin and copper.

 

38) 2.76 g of silver carbonate on being strongly heated yields a residue weighing
(a) 2.16 g (b) 2.48 g (c) 2.32 g (d) 2.64 g
Answer: A.

 

39) Which is the most widely used metal?

Answer: Iron.

 

40) How would you know that a chemical is pure or not?

Answer: By checking its melting point.

 

41) Which mineral is used making plaster and paper?

Answer: Gypsum.

 

42) M is the molecular weight of KMnO4. The equivalent weight of KMnO4 when it is converted into K2MnO4 is
(a) M (b) M/3 (c) M/5 (d) M/7
Answer: A.

 

43) Which is the metal as strong as steel but half as much in weight?

Answer: Titanium.

 

44) Which material is used in display devices, such as digital watches?

Answer: Liquid crystal.

 

45) Which metal is extracted by the Mond process?

Answer: Nickel.

 

46) If 0.50 mole of BaCl2 is mixed with 0.20 mol of Na3 PO4, the maximum number of moles of Ba3 (PO4) 2 that can be formed is
(a) 0.70 (b) 0.50 (c) 0.20 (d) 0.10
Answer: D.

 

47) Which is the most stable compound?

Answer: Sodium hydroxide.

 

48) Which chemical compound may soon be used as a fuel for driving vehicles?

Answer: Ethanol.

 

49) What is the purest form of iron?

Answer: Wrought iron.

 

50) One mole of N2H4 loses ten moles of electrons to form a new compound Y. Assuming that all the nitrogen appears in the new compound, what is the oxidation state of nitrogen in Y? (There is no change in the oxidation state of hydrogen).
(a) –1 (b) –3 (c) +3 (d) +5
Answer: C.

 

General Chemistry Questions and Answers – Learn Basic Chemistry Part 3 (51-75)

 

51) Which substance is obtained when magnesium is heated with lead oxide?

Answer: Mgo + Pb.

 

52) Which drug is present in cola drinks?

Answer: Caffeine.

 

53) What do you mean by horn silver?

Answer: Ore of silver, that is AgCl.

 

54) The oxidation number of carbon in CH2O is
(a) – 2 (b) + 2 (c) 0 (d) + 4
Answer: C.

 

55) Which mineral ores forms kidney-shaped crystals?

Answer: Haematite.

 

56) Which fuel produces the maximum heat per gram burnt?

Answer: Hydrogen.

 

57) Which mineral is often used as an abrasive?

Answer: Corundum.

 

58) A molal solution is one that contains one mole of a solute in:
(a) 1000 g of the solvent (b) one liter of the solvent (c) one liter of the solution (d) 22.4 liters of the solution
Answer: A.

 

59) What is an amalgam?

Answer: Mixture of metal and mercury.

 

60) Which element in the radioactive form is used for determining the age of artifacts, relics, bones, etc. of the past?

Answer: Carbon.

 

61) What is Pyrolusite?

Answer: Ore of manganese, Mn02.

 

62) In which mode of expression, the concentration of a solution remains independent of temperature?
(a) Molarity (b) Normality (c) Formality (d) Molality
Answer: D.

 

63) Which elements impact corrosion resistance to steel?

Answer: Nickel.

 

64) Which product of living organisms was the first to be made under laboratory conditions?

Answer: Urea.

 

65) What do you mean by polling?

Answer: Stirring of molten metal with green wood.

 

66) An aqueous solution of 6.3 g oxalic acid dihydrate is made up to 250 ml. The volume of 0.1 N NaOH required to completely neutralize 10 ml of this solution is
(a) 40 ml (b) 20 ml (c) 10 ml (d) 4 ml
Answer: A.

 

67) Where lies the biggest deposit of gold?

Answer: Ballarat.

 

68) Which drug is present in tobacco?

Answer: Nicotine.

 

69) What is galvanising?

Answer: Coating iron with Zinc.

 

70) Which has a maximum number of atoms?
(a) 24g of C (12) (b) 56g of Fe (56) (c) 27g of Al (27) (d) 108g of Ag (108)
Answer: A.

 

71) What do you mean by calcination?

Answer: Heating in the absence of air.

 

72) What is the most common natural source for sulfur?

Answer: Volcanic region.

 

73) Which are the major gaseous components of air?

Answer: Argon, Oxygen, Carbon di oxide, Nitrogen.

 

74) Consider a titration of potassium dichromate solution with acidified Mohr’s salt solution using diphenylamine as an indicator. The number of moles of Mohr’s salt required per mole of dichromate is
(a) 3 (b) 4 (c) 5 (d) 6
Answer: D.

 

75) What is the trade name for fluoride ore of calcium?

Answer: Fluorspar.

 

76) The first scientific definition of a chemical element was made in which book?

Answer: The Sceptical Chymist.

 

Top Chemistry Questions and Answers – Learn the Basics of Chemistry Part 4 (76-100)

 

 

77) Which is the first alloy, a mixture of two metals to be made in the world?

Answer: Bronze.

 

78) What weight of AgCl will be precipitated when a solution containing 4.77 g of NaCl is added to a solution of 5.77 g of AgNO3?
Answer: 4.87 g.

 

79) What is the percentage of carbon in steel?

Answer: 0.2 – 2.0%.

 

80) Which element is present in the least amount in a living body?

Answer: Manganese.

 

81) Which mineral was used for making compasses in the past?

Answer: Magnetite.

 

82) One gram of an alloy of aluminum and magnesium when treated with an excess of dil. HCl forms magnesium chloride, aluminum chloride, and hydrogen. The evolved hydrogen, collected over mercury at 0°C has a volume of 1.20 liters at 0.92 atm. pressure. Calculate the composition of the alloy. [H = 1, Mg = 24, Al = 27]
Answer: Al 54.87%, Mg 45.13%.

 

83) What kind of metals are generally extracted by electrolysis?

Answer: Alkali and alkaline earth metals.

 

84) What is Manganese?

Answer: A hard brittle greyish-white metallic element.

 

85) Which rocks, is used as stones for building houses?

Answer: Oolite.

 

86) 4.215 g of a metallic carbonate was heated in a hard glass tube and the CO2 evolved was found to measure 1336 ml at 27°C and 700 mm pressure. What is the equivalent weight of the metal?

Answer: 8.38.

 

87) What do you mean by Cinnabar?

Answer: Ore of mercury, HgS.

 

88) Which gas liberated when marble reacts with hydrochloric acid?

Answer: Co2.

 

89) Where was the technique of powder metallurgy invented?

Answer: India.

 

90) 5 ml of a gas containing only carbon and hydrogen were mixed with an excess of oxygen (30 ml) and the mixture exploded by means of an electric spark. After the explosion, the volume of the mixed gases remaining was 25 ml. On adding a concentrated solution of potassium hydroxide, the volume further diminished to 15 ml of the residual gas being pure oxygen. All volumes have been reduced to N.T.P. Calculate the molecular formula of the hydrocarbon gas.

Answer: CH4.

 

91) Write the two processes by which desilverisation of lead is done:

Answer: Parkes process, Pattison’s Process.

 

92) Which substance is produced when nitrogen reacts with hydrogen?

Answer: Ammonia.

 

93) Where does Natural diamond occur?

Answer: Kimberlite.

 

94) In the analysis of 0.500 g sample of feldspar, a mixture of chlorides of sodium and potassium is obtained which weighs 0.1180g. Subsequent treatment of mixed chlorides with silver nitrate gives 0.2451g of silver chloride. What is the percentage of sodium oxide and potassium oxide in feldspar?

Answer: Na2O = 3.58%, K2O = 10.62%.

 

95) What is Hematite?

Answer: Ore of iron, Fe203.

 

96) Which metal has the density is less than that of water?

Answer: Sodium.

 

97) Which mineral is used in jewellery?

Answer: Garnet.

 

98) A compound contains 28 percent of nitrogen and 72 percent of metal by weight. 3 atoms of metal combine with 2 atoms of N. Find the atomic weight of metal.
Answer: 24.

 

99) Which iron contains a high percentage of carbon?

Answer: Pig iron.

 

100) Which catalyst used in the manufacture of Sulfuric acid?

Answer: Vanadium pentoxide.

 

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