12th class (Fsc) Chemistry unit 4 MCQs
51. The geometrical shape of PCI5 is:
a. Trigonalbipyramidal
b. Octahedral
c. Tetrahedral
d. Square planer
52. PCI5 is kept in well stoppered bottled beause:
a. It reacts with oxygen
b. It is highly volatile
c. It is explosive
d. It reacts readily with moisture
53. Phosphorus pentachloride sublimes at about:
a. 100oC
b. 50oC
c. 80oC
d. 70oC
54. What is the smell of fumes given by PCI5 in moist air?
a. Fruity
b. Irritating
c. Garlic like
d. Pleasant
55. PCI5 is kept in well stoppered bottled because:
a. It react with oxygen
b. It is highly volatile
c. It is explosive
d. It reacts readily with moisture
56. What is the smell of fumes given by PCL3 in most air?
a. Fruity
b. Irritating
c. Garlic like
d. Pleasant
57. What are the possible products for hydrolysis of PCI5 ?
a. H3PO4+HCL
b. H3PO3+HCL
c. H3PO3
d. PH3+HCIO
58. The phosphorus acid is a powerful:
a. Dehydrating agent
b. Oxidizing agent
c. Acid
d. Reducing agent
59. When phosphorus trichloride dissolve in water, then it is converted into:
a. Ortho phosphoric acid
b. phosphorus acid
c. Pyro-phosphoric acid
d. Meta-phosphorus acid
60. In V-A group which element has highest boliling point?
a. Bi
b. As
c. P
d. Sb
61. H3PO3 act as:
a. Dehydrating agent
b. Reducing agent
c. Oxidizingm agent
d. None of these
62. The oxidation state of S in S2CI2 is:
a. +3
b. +1
c. +4
d. +2
63. Phyrohosporic acid:
a. H4P2O7
b. HPO3
c. H3PO4
d. H2P2O7
64. Ortho-phosphoric acid is converted into pyro-phosphoric acid at:
a. 200oC
b. 100oC
c. 240oC
d. 150oC
65. Phyrophosphoric is converted into meta-phosphoric acid at:
a. 340oC
b. 316oC
c. 350oC
d. 216oC
66. What is the final product of hydrolysis of p2O3?
a. H6P4O13
b. H3PO3
c. (PHO3)4
d. None of these
67. What is the possible product when P2O3 is treated with cold water?
a. H3PO4
b. HPO3
c. H3PO3
d. H2PO3
68. What are the possible product when P2O3 is treated with hot water?
a. H3PO4+HCI
b. H3PO3+HCI
c. H3PO3+CI2
d. PH3+H3PO4
69. Which one of the following is obtained by heating H3PO4 to 60oC?
a. HPO3
b. P2O5+3H2O
c. H4P2O7
d. H3PO5
70. Which one of the following molecule is paramagnetic in nature?
a. H2
b. N2
c. O2
d. He
71. All the elements of oxygen family are:
a. Non-metals
b. Radioactive
c. Metalliods
d. Polymorphoric
72. The elements of group VIA elements are called chalogens from the Greek work meaning:
a. Salt former
b. Copper giver
c. Light bearnig
d. None of these
73. What is the general electronic configuration Of VIA group elements:
a. ns2np2
b. ns2np4
c. ns2np5
d. ns2np3
74. Which of the following cannot expand its outer shell of electrons beyond octet?
a. Se
b. O
c. Te
d. S
75. Which element forms about 50% earth’s crust?
a. Sulphur
b. Phosphorous
c. Carbon
d. Oxygen