Chemistry Important Questions
Chemistry Important Questions and Answers Part 1
Chemistry Important Questions 1-30
1) A rain coat is made of what?
2) Which element on adding to natural rubber makes it less sticky in hot weather and less hard in cold weather?
3) Which chemical causes Minamata disease?
4) The absence of cobalt in minute quantities in human body causes what?
Answer: Pernicious anaemia.
5) Which element can easily form chains?
6) Cement mixed with gravel, sand and water is called what?
7) What is the measure of performance of petrol in internal combustion engines?
Answer: Octane number.
8) Glass is made out of what?
9) Which is considered to be an anomalous compound?
10) How would you know that a chemical is pure or not?
Answer: By checking its melting point.
11) Which material is used in display devices, such as digital watches?
Answer: Liquid crystal.
12) Which chemical compound may soon be used as a fuel for driving vehicles?
13) Which drug is present in cola drinks?
14) Which fuel produces the maximum heat per gram burnt?
15) Which element in radioactive form is used for determining the age of artifacts, relics, bones etc. of the past?
16) Which product of living organisms was the first to be made under laboratory conditions?
17) Which drug is present in tobacco?
18) What is the most common natural source for sulfur?
Answer: Volcanic region.
19) The first scientific definition of a chemical element was made in which book?
Answer: The Sceptical Chymist.
20) Which element is present in the least amount in a living body?
21) What is Manganese?
Answer: A hard brittle greyish-white metallic element.
22) Which gas liberated when marble reacts with hydrochloric acid?
23) Which substance is produced when nitrogen reacts with hydrogen?
24) Which metal has the density is less than that of water?
25) Which catalyst used in the manufacture of Sulfuric acid?
Answer: Vanadium pentoxide.
26) What do you mean by orbitals?
Answer: They are regions of space around the nucleus where the probability of finding an electron is maximum.
27) What are the integers used to express the energy, position etc. of an electron?
Answer: Quantum numbers.
28) Which are the major shells that do not possess f – subshell?
Answer: The major shells K, L, and M do not have f subshell.
29) The atomic number of potassium is 19. The sub-shell-wise electronic configuration of its atom is what?
Answer: Is2, 2s2, 2p6, 3s2, 3p6, 4s1.
30) The major shell which does not possess p-orbitals is what?
Chemistry Important Questions and Answers Part 2
Chemistry Important Questions 31-60
31) What is the principle in the order of the filling of electrons in the atoms?
Answer: The principle is that the orbitals of the lower energy levels are filled up before an electron enters an orbital of a higher energy.
32) The principle stating that the position and momentum of a sub-atomic particle cannot be determined simultaneously is called what?
Answer: Uncertainty principle.
33) What do you mean by Avogadro’s number?
Answer: Number of particles in one mole of any substance.
34) What is the minimum angular momentum of an electron?
35) The wave nature of electron was suggested by whom?
36) Which electron has least energy?
Answer: ‘K’ electrons.
37) 2p, 3s, 3d, 4s of these which one has highest energy?
38) The 3p orbital is completely filled in what?
39) What is meant by sub-energy levels?
Answer: Sub-energy levels or subshells are groups or orbitals having a particular shape.
40) The outermost five electrons of an atom are in 2p orbitals. Its atomic number is what?
41) The atom which has 4s1 electron in its outermost shell is that of what?
42) In the formula 2n2, n denotes what?
Answer: Number of orbit.
43) The number of electrons in oxygen atom is what?
44) How much is the electronic configuration of helium?
45) The number of orbitals present in Sodium atom is what?
46) How much is the maximum number of orbitals present in N shell?
47) What is the total number of ‘p’ electrons present in an element having atomic number 19?
Answer: 12 ‘p’ electrons (2p6 + 3p6 ).
48) The reaction in which the forward and backward reactions occur simultaneously 1 is called what?
Answer: Reversible reaction.
49) A substance which sublimes is what?
Answer: Ammonium chloride.
50) What do we get on oxidizing sulfur dioxide?
Answer: Sulfur trioxide.
51) Which substance (in white colour) seen on the inner side of the test tube near its mouth when ammonium chloride is heated in it?
Answer: Ammonium chloride.
52) Those reactions in which the products cannot react and give back the original reactants are called what?
Answer: Irreversible reactions.
53) What is the name of the chemical with formula KCNS?
Answer: Potassium thiocyanate.
54) The temperature most suited for conducting an industrial process involving a reversible reaction; most conveniently and profitably is called what?
Answer: Optimum temperature.
55) The reaction in which product molecules react and give back the original reactants is called what?
Answer: Backward reaction.
56) A system of reacting substances from which neither-the reactants nor the products are taken away or added to is called what?
Answer: Closed system.
57) The electrical charge possessed by a hydroxyl ion is what?
Answer: Unit negative.
58) When electrolysis takes place, where the products are obtained?
Answer: At the electrodes.
59) In a hydroxyl ion how many number of electrons on the whole?
60) A substance which conducts electricity by the movement of ions?
Answer: Common salt solution.
Chemistry Important Questions and Answers Part 3
Chemistry Important Questions 61-85
61) Which non-metal conducts electricity by the movement of electrons?
62) In an electrolyte the substance is present as ions even before the passing of electricity though it. Who suggested this theory?
Answer: Svante Arrhenius.
63) Where is the addition of electron takes place?
64) Write an example for dibasic acid:
Answer: Sulfuric acid.
65) Which is formed when two hydrogen ions are removed from phosphoric acid?
Answer: Monohydrogen phosphate.
Chemistry Exam Questions
66) Which is the electrolyte used in anodisation?
Answer: dil. H2S04.
67) The acid salt of Sulfuric acid is:
Answer: Bisulfate (Acid sulfate).
68) Write an example of electrolyte:
Answer: Sodium chloride solution.
69) Substances that do not conduct electricity are called what?
70) What do we get when Potassium manganate is oxidized?
Answer: Potassium permanganate.
71) Which metal is used as electrode in the electrolysis of Copper sulfate solution?
72) Which metals are used for electroplating?
Answer: Gold, Silver, Copper, Nickel.
73) What is electroplating?
Answer: Coating a metal over another metal using the process of electrolytic dissociation is called electroplating.
74) Electrode that is connected to the positive pole of the battery is called what?
75) In a torch cell, which energy is converted into electric energy?
76) What is Ionization?
Answer: The dissociation of a substance into its ions is called Ionization.
77) Write an example of compounds manufactured by electrolysis:
Answer: Sodium hydroxide.
78) Write an example of Tribasic acid:
Answer: Phosphoric acid.
79) The cations in water are which ions?
80) What we get when hydroxyl ions get discharged?
Answer: Water and oxygen.
81) What happened when the pressure of a gas is increased?
Answer: Its concentration is also increases.
82) What is the molecular formula of ammonia?
83) Write an example of an alkali:
84) Which energy is possessed by the activated complex?
Answer: Potential energy.
85) Write an example for one-way reaction:
Answer: Burning of magnesium.