(Important Questions) Important Questions Class XII Chemistry (2009) Set - VI
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Important Questions Class XII Chemistry (2009) Set - VI
Chemistry
Q. 51. HCl and HNO3 are prepared by reacting NaCl and NaNO3
respectively with H2SO4 while
HBr and HI can be prepared by this method.
Q. 52. Cane sugar chars in concentrated sulphuric acid.
Q. 53. Concentrated sulphuric acid is a good oxidizing agent.
Q. 54. Two S-O bonds in SO2 are equivalent.
Q. 55. Ka2 of H2SO4 is <<>1.
Q. 56. Halogens have maximum negative electron gain enthalpy in each period.
Q. 57. Fluorine has lesser negative value of electron gain enthalpy than chlorine.
Q. 58. All halogens are colored.
Q. 59.F2 has smaller enthalpy of dissociation than Cl2.
Q. 60. Fluorine has lesser negative value of electron gain enthalpy than chlorine but fluorine is a stronger oxidizing agent than chlorine.
Q. 61. Fluorine shows only a 1 oxidation state. Other halogens can exhibit positive oxidation state.
Q. 62. Halogens show positive oxidation state when they combine with oxygen and fluorine atoms.
Q. 63. Halogens are good oxidizing agent and oxidizing power (reactivity) decreases with the increase in atomic number.
Q. 64. Most of reactions of fluorine are exothermic.
Q. 65. HF is a liquid while other hydrogen halides are gases.
Q. 66. HF has highest boiling point while HCl has lowest boiling point among hydrogen halides.
Q. 67. Acidity of hydrogen halides HF <>
Q. 68. Thermal stability of hydrogen halides HF > HCl > HBr > HI
Q. 69. Thermal stability of group 16 hydrides H6O > H6S > H6Se > H6Te
Q. 70. OF2 is fluoride of oxygen and not oxide of fluorine.
Q. 71. Oxygen and chlorine has similar electro negativity. Oxygen form hydrogen bonding but not chlorine.
Q. 72.Ionic character of halides MF>MCl>MBr>MI
Q. 73. Electron gain enthalpy of O O- is a 141 KJ/mole and O O --> O2-
is + 702 KJ/mole.
Large number of oxides having O2- is known and not O-.
Q. 74. In metal halides, halides in higher oxidation state of the
metal is more covalent than
the one in lower oxidation state.(PbCl4 is more covalent than PbCl2)
Q. 75. Inter halogen compound is more reactive than the halogens from which it is formed.
Q. 76. Chlorine is a powerful bleaching agent.
Q. 77.HCl reacts with Fe to give FeCl2 and not FeCl3
Q. 78. Fluorine forms only one oxo acid HOF
Q. 79. Acidity of oxo acids HClO4> HClO3> HClO2> HC1O.
Q. 80. Acidity of oxo acids HOCl>HOBr>HOI
Q. 81. Oxidizing power of HClO4> HClO3> HClO2> HClO
Q. 82. Fluorine form fluoride of oxygen while other halogens form oxides of halogen.
Q. 83. Group 18 elements are chemically uncreative.
Q. 84. Group 18 elements have very high ionization enthalpy and it decreases on going down the group.
Q. 85. Group 18 elements have positive value of electron gain enthalpy.
Q. 86. Group 18 elements have lower value of boiling and melting point and it increases on going down the group.
Q. 87. Group 18 elements have larger atomic radius.
Q. 88. Bartlett synthesized XePtF6 from his knowledge of earlier known compound O2PtF6.
Q. 89. Xenon forms noble gas compounds.
Q. 90. Xenon forms compounds only with oxygen and fluorine.
Q. 91. Helium is used in diving apparatus.
Q. 92. Oxygen has lesser negative value of electron gain enthalpy than Sulphur.
Q. 93. What type of defect reduces the density of unit cell?
Q. 94. What is the effect of temperature on osmatic pressure of the solution?
Q. 95. Determine the order of the reaction if its half life is inversely proportional to the initial concentration of the reactant.
Q. 96. Mention two uses of formaldehyde.
Q. 97. Write the IUPAC name of the compound CH3 OCOCH2 CH2 COO CH3
Q. 98. What do you understand by radial probability function 4pr2R2? Draw the radial probability function curve for 2s and 2p orbital.
Q. 99. Comment on the validity of the following statements:
1. A reaction with DG0< 0 has always equilibrium constant greater than 1.
2. An exothermic reaction is always spontaneous.
Q. 100. The outer electronic configuration of two elements of lanthanoids are given below
1. 4f1 5d1 6s2
2. 4f7 5d0 6s2. Determine the atomic number of these elements.
Determine the stable oxidation state of these elements.
Q. 101. Give two differences between conformational isomerism and configurational isomerism.
OR
A compound having two chiral centers does not always have four stereo isomers. Justify this statement with a suitable example.
Q. 102. Mention the differences between thermo setting and thermo plastic polymers.
Q. 103. Distinguish chemically between
1. Phenol and methanol
2. Propan-1-ol andpropan-2-ol.