Chemistry – Important Question Bank for Bihar BSEB 2016 Examination

1. A Solid is made up to two elements pand Q. Atoms of Q are in CCP arrangement, while atoms of P occupy all the tetrahedral sites what is the formula to the compound ?
2. Why does table salt Nacl sometimes appear yellow in colour ?
3. What is the Non- stoichiometric defect in crystals ?
4. Chromium crystallizes in BCC structure if the atomic diamater is 215pm, find the density Atomic mass of cr = 52 and No = 6.022×10²³
5. What is the coordination number of –
   • Zinc in Zincblende(zns)
   • Oxide ion in sodium oxide(Na₂O)
   • Calcium in calcium fluoride (CaF₂)
   • Distinguish between-
   • Crystal lattice and unit cell.
   • Tetrahedral and Octahedral void.
6. Calculate the mole fraction of benzeac ub silution contaning 30% by mass in carbon tetrachloride.
7. Boiling point to water at 750 _mm Hg is 99.67⁰ C How much sucrose should be added to 500 gm of water so that it boils at 100⁰ C ?
8. Difine Depressin of freezing point.
9. Vapour pressure of water at 293 K is 17.535 mm Hg calculate the vapour pressure of solution at 293 k when 25 gm of glucose is dissolved in 450 g of water.
10. What would be the value of vent hoff factor for a dilute solution of K 250₄ in water.
11. The Fpt of 5%(by mass) sucrose solution is 271 k. if the pure water is 273.15 k, then find out the F.pt of 5% glucose soln.
12. Define an equation to express that relative lowering of vapour pressure for a solution is equal to the mole fraction of the solute is it when the solvent alone is volatile.
13. A decimolar solution of potassium ferro cyanide is 50% dissociated at 300 k calculate the osmotic pressure of the solution               (R = 8.314 JK-¹mol-¹)
14. Explain kohlrausch’s Law of Independent migration of ons. Mention one application of this law.
15. Why does the conductivity of a solution decrease with dilution ?
16. Explain the proceed of recharging of lead storage battery.
17. Depict the galvanic cell in which the reaction zn(s)+2Ag⁺(aq)→zn²⁺+2Ag(s) takes place. Further show-
18. Which of the electrode is negatively charged ?
19. Individual reaction at each electrode ?
20. Define conductivity and molar conductivity for the solution of an electrolyte. Discuss their variation with concentration.
21. Why is molecularity applicable only for elementary reactions and order is applicanle for elementary as well as complex reactions?
22. A first order reaction is 20% complete in 10 minutes Calculate the time for 75% completion of reaction.
23. Distinguish between order and molecularity of a reaction.
24. A reaction is of second order with respect to a reactant. How is the rate of reaction affected if the concentration of the reactant is reduced to half ? What is the unit of rate constant for such a reaction.
25. Distinguish between ‘rate expression’ and ‘rate constant of a reaction.
26. What are the factors, which influence the adsorption of a gas on a solid.
27. What is dcmulsification name two demulsifiers.
28. State the reason in each of the following cases:
29. Soaps do not work well in hard water
30. Synthetic detergents are better than soaps.
31. what is shape selective catalysis.
32. Explain the following term with suitable examples : A)Alcosol  B) Aerosol, C) Hydrosol
33. How does a catalyst work. Indicate a chemical reaction involving homagenous catalyst.
34. Co2 is a better reducing agent below 710 K Whereas Co is a better reducing agent above 710 K. explain.
35. Why generally sulplideores are converted into Oxides before redvetion.
36. Silica is added to the sulplide ore of copper in the reverbatory furnace. Explain
37. Why C and H are not used as reducing agents at high temperature.
38. Which is the most abundant element is the earth crust ?
39. Which is the most abundant Metal is the earth crust ?
40. Name the metal present in the (a) chlorophy II (b) Haemoglobin.
41. What is the Common ore of Hg ?
42. What types of ores roasted ?
43. How is copper pyrites Concentrated?
44. What name is given to carbon reduction process for the extraction of Metal ?
45. Give one example where hydrometallurgy is used for metal extraction.
46. What is Flex and in which operation is it used ?
47. Name the products formed when Zinc pyrites is roasted ?
48. In which furnace Calcination and Roasting are normally carried out ?
49. Name the following:-
    • Two metals which never occur in Native State.
    • Two metals which always occur both Native & Combined State.
    • Two metals which always occur in an Uncombined State.
50. Name the metals with which the following ares/minerals are associated (i)-Cryolite (II) Dolomite (iii) Calamine (iv) Haimatite (v) Malachite.
51. Name any two metals which are manufactured by the Electrolysis of their fused salts ?
52. How is poling Carried out? Which metal is purified by this Method ?
53. Indicate the Temp. at which C can be used as a reducing agent for Fee.
54. Which is a better reducing agent below 983K (7100c) Carbon or Carbon Monoxide ?
55. In Blast furnace during extraction of Fe from oxide ore which acts as a reducing agent, C or CO
56. How is Cast Iron different from Pig Iron ?
57. Name the process from which chlorine is obtained as a by product ?
58. Name the Common Elements present in the Anodic mud in Electrolytic refining of copper.
59. Why do a few elements occur in the notive state while others do not ?
60. Give reason:-
    • Why in Zn and not Cu used for the recovery of metallie Ag from its Cyanide complex {Ag(CN)2}.
    • Why does Ca react with silica to from a slag ?
    • Why is the formation of sulphate in Calcination some times advantageous ?
    • How can you separate Alumina from silica in a Bauxite ore associated with silica ? Give examples only.
    • How can the following impurities be removed ?
    • An impurity of Pb in Ag (b) Impurities of Fe, Cu, etc in Al.
61. Which Compounds in each of the following pairs will react faster in SN2 reaction with OH ?
62. CH3 Br or CH3I (ii) (CH3)3 CCL or CH3CL (iii) H2C= CHBr or H2C= CH-CH2 Br
63. Arrange the following in decreasing order of reactivity towards SN1 reaction:
64. CH3Br, CH3CH2 Br, (CH3)2 CHBr, (CH3)3 C-Br, C6H5CH2Br, H2C=CH-CH2Br
65. Arrange the following in decreasing order of nucleophilicity:-
66. F-, Br-, I-, CL-, (ii) H2o, -OH, -OR, Rcoo
67. Arrange the following in the increasing order of boiling point:-
68. (CH3)3 C-Br (ii) (CH3)3 C-CL (iii) CH3CH2CH2CH2Br (iv) CH3CH(Br)CH2CH3
69. Name the product when benzene diazonium chloride is warmed with aqueous KI.
70. Out of benzyl chloride and chlorobenzene which will gives a white precipitate with AgNo3 solution ?
71. Name the product when iodobenzene is heated with copper powder at 475 K in a sealed tube
72. Give reagents inorganic or organic needed to convert benzyl chloride into:-
    • Benzyl aleohol
    • Benzly iodide
    • Benzyl cyanide
    • Benzyl ethyl ether
    • Benzyl acetate
    • Phenyl nitromethane
    • txi-n-butyl benzyl ammonium chloride
73. Name the product obtained when chloroform reacts with (a) acetone (b) nitric acid (c) silver powder (d) aniline in the presence of alcoholic KOH (e) Zine dust and Water.
74. Which Compounds or groups give iodoform test ?
75. Give the chemical name and formulae of the following compounds:-Freon (ii) Teflon (iii) Westron (iv) Westrosol
76. Although Chlorine is an electron with drawing group yet it is ortho-para- directing in electrophilic aromatic substitution reactions why ?
77. Why is sulphuric acid not used during the reaction of alcohols with KI ?
78. Arrange each set of compounds in order of increasing boiling points:- (i) Bromomethane, Bromoform, Chloromethane, Trichloromethane, Dichloromethane (ii) Chloropropane, Isopropyl chloride, 1-chlorobutane
79. How will you bring about the following conversions ?     (i)Ethanol to but-1-yne
    (ii) Ethanol to bromoethane
    (iii) Propene to 1-nitropropane
    (iv)Toluene to benzyl alcohol
    (v) Propene to propyne
    (vi) Ethanol to ethyl fluoride
    (vii) Bromomethane to propanone
    (viii) But-1-ene to but-2-ene (ix) 1- chlorobutane to n-octane
    (x) Benzene to biphenyl
80. What is the difference between monomers and polymers ? How polymers are classified on the basis of:-
81. Source (ii) Synthesis (iii) Structure and (iv) Molecular forces involved. Explain with examples.
82. Explain the following terms with suitable examples:-(i) Copolymers
    (ii)Additional polymers
    (iii) Condensation polymers
    (iv) Elastomers
    (v)Chain-growth polymerization
    (vi) Step-growth polymerization
    (vii) Natural polymers
    (viii) Synthetic polymers
    (ix) Biopolymers
    (x)Biodegradable polymers
83. What are (i) Soft Soaps and (ii) Hard Soaps ?
84. What are micelles ?
85. Explain the role of phosphate in detergent powder ?
86. What are the Consequence of using non-biodegradable detergents?
87. What are Soft and hard detergents?
88. Sleeping pills are recommended by doctors to the patients suffering from sleeplessness but it is not advisable to take their doses without Consultation with the doctor, Why ?
89. Read the following Statement:
90. “Ranitidine is an antacid” with reference to which classification has this statement been given:-
91. Why do we require artificial sweetening agents?
92. What is thermosetting polymer?
93. What is homopolymer?
94. What is copolymer?
95. What is additional polymer?
96. What is PVC?
97. What is a Semiconductor ? Describe the two main types of Semiconductors and explain the mechanism for their conduction.
98. Calculate the packing efficiency of a metal crystal for a simple cubic lattice.
99. Aluminium crystal allies in a cubic close packed structure. Raduis of the atom in the metal is 125 pm.
100. What is the length of the side of the unit cell
101. How many unit cells are there in 1cm3 aluminium
102. If the raduis of the octahedral void is r and the raduis of the atoms in the close packing is R, derive relationship between r and R.
103. What is ferromagnetism and paramagnetism. How is ferromagnetism different from paramagnetism.
104. How would you account for the following ?
105. Frenkel defects are not found in alkali metal halides.
106. Schottky defects lower the density of related solids.
107. Impurity doped silicon is a semiconductor.
108. Vapour pressure of Chloroform (CHCL3) and dichloromethane (CH2CL2) at 298 k are 200mm Hg and 415 mm Hg respectively.
109. Calculate the vapour pressure of the solution prepared by mixing 25.5g of CHCL3 and 40 g of CH2CL2 at 298 k.
110. Calculate the mole fraction of each Component in vapour phase
111. Which aqueous solution has higher concentration 1 molar or 1 molat solution of the same solute ? Give reason.
112. 5g KCL was dissolved in 100 g water and the solution originally at 200 C froze at -0.240 C calculate the percentage ionisation of salt kf per 1000 g of water = 1.86 k
113. What are Carbohydrates? Explain.
114. How benzene diazonium chloride is prepared?
115. What happens when :
116. Methyl bromide is treated with Sodium in presence of dry ether?
117. Methyl chloride is treated with KCN?
118. How ethyl amine is prepared in the lab?
119. Give the lab preparation methyl amine?
120. What catalysts are used in contact process? Write their names and optimum temperature working.
121. How ethyl chloride is prepared in the laboratory?
122. How chloroform is industrially prepared?
123. How do you prepare CHI3 (Iodoform) in the lab?
124. How chlorobenzene is obtained from benzene diazonium chloride?
125. How do you prepare ethanol in the lab?
126. How ethanol is commercially manufactured?
127. How carbenol (methanol) is prepared commercially?
128. How will you distinguish primary, secondary and tertiary alcohols? Give two tests.
129. Distinguish between aldehyde and and ketone?
130. Distinguish between methanoic acid and ethanoic acid?
131. How is ethanal prepared in the lab?
132. Give the lab method of preparation of acetone?
133. Give the commercial method of preparation of vinegar?
134. How the following conversions can be carried out?
     • Propene to Propan-1-ol
     • Ethanol to But-1-yne.
     • How the following conversions can be carried out?
     • Ethanol to propane nitrile
     • Aniline to Chlorobenzene.
135. How the following conversions can be carried out?
     • 2-Chlorobutane to 3,4-Dimethyl hexane
     • 2-Methyl-1-propane to 2-chloro-2-methyl propane
136. What happens when
     • n-Butyl chloride is treated with alcoholic KOH?
     • Bromobenzene is treated with Mg in the presence of dry ether?
137. What is Gibbs free energy ? What is the relationship between Gibbs free energy of the cell reaction in a galvanic cell and the emf of the cell. When will the maximum work be obtained from a galvanic cell.
138. Explain the following terms.
     • Rate of a reaction
     • Activation energy of a reaction
139. Discuss the effect of pressure and temperature on the adsorption of gases on solid.
140. What do you mean by activity and selectivity of catalyst ?
141. What are lyophilic and lyophobic sols ? Give one example of each type. Why is lyophobic sols ?
142. What are micelles ? How do they differ from ordinary colloidal particles ? Give two example of micell forming substance.
143. State Hardy – Schulze rule
144. Taking two examples of heterogeneously catalyzed reaction, explain how a heterogeneous catalyst helps in the reaction.
145. State Raoult’s Law for a solution. How does Raoult’s law became a special case ofvHenry’s law
146. 00g of a non-electrolyte solute dissolved in 50g of benzene lowered the freezing point of benzene by 0.40k. Find the molar mass of the solute ( Kf for benzene = 5.12 kkg mol-1)
147. How do the elements occur in nature? Name the chief form of occurrence of the following in the earth’s crust :Aluminium (b) Iron (c) Copper (d) Zinc
148. What is meant by the term “concentration of the ore”? Describe the various methods used for this purpose.
149. Describe briefly the various methods used for refining of crude metals.
150. Describe the various methods used for obtaining metals from the concentrated ores.
151. Describe the principle of extraction of each of the following:
152. Cu from CuFeS2 (ii) Zn from ZnO (iii) Fe from Fe2O3
153. Describe the electro-chemical principles of metallurgy. Apply these principles in the extraction of aluminium from alumina and Copper from low grade ores and scraps.
154. Explain the following :

(i) Carbon reduction process is not applied for reducing alumina to aluminium.

(ii) Aqueous solution of Sodium chloride cannot be used for isolation of solution by electrolysis.
(iii) Graphite is used as anode and not diamond.
(iv) Magnesium oxide is often used as the lining in steel making furnaces.

155. Write short notes on :(i) leaching (ii) Hydro-metallurgy (iii) Column chromatography (iv) Zone refinning

156. Explain, with proper reason, why nitrogen is a gas while other members of group-15 are solids.

157. PCl5 is known, but PI5 not. Why?

158. Why conc. H2SO4, anhydrous CaCl2 or P4O10 cannot be used as dehydrating agents for ammonia?

160. H3PO3 is diprotic (or dibasic). Why?

161. Oxygen is a gas while Sulphur is a Solid. Explain.

162. Water is a liquid while H2S is a gas. Explain.

163. Sulphuric acid has high boiling point and viscosity. Explain.

164. Sugar turns black on addition of conc. H2SO4. Explain

165 . How will you obtain the following from Sulphuric acid?

(i) SO2 (ii) SO2Cl2 (iv) H2S (v) S

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