P – BLOCK ELEMENTS – 26

1) Bleaching powder is obtained by the action of chlorine gas on a) b) c) Dry CaO d) Dry slaked lime 2) Mark the element which shows only one oxidation state: a) F b) Cl c) Br d) I 3) Which of the following halogens has the highest bond energy? a) b) c) d) 4) …

P – BLOCK ELEMENTS – 28

1) Which species is not known? a) b) c) d) 2) The geometry of the XeOF4 molecule is a) Square planar b) Square pyramidal c) Triangular pyramid d) Distorted octahedron 3) In order to prevent the hot metal filament from being burnt up when the electric current is switched on, the bulb is filled with …

P – BLOCK ELEMENTS – 27

1) On heating KCIO3 we get a) b) c) d) 2) The correct order of increasing oxidizing power is a) b) c) d) 3) Freon is used as a a) Refrigerant b) Catalyst c) Oxidant d) Both (b) and (c) 4) Which of the following halogens does not exhibit a positive oxidation state in its …

P – BLOCK ELEMENTS – 29

1) Iodine is formed when KI reacts with a solution of a) Zn SO4 b) Cu SO4 c) Fe SO4 d) (NH4)2 SO4 2) Bromine gas turns starch iodide paper a) Blue b) Red c) Colourless d) Yellow 3) The melting point of Astatine is a) 572 K b) 472 K c) 372 K d) None of the above …

P – BLOCK ELEMENTS – 18

1) Which of the following does not show allotropy ? a) N b) P c) Bi d) As 2) The molecule NO is described as a) Odd-electron molecule b) paramagnetic c) very reactive d) All the above 3) NO2 is a/an a) b) c) d) 4) In the reduction of HNO3 to N2O, the number …

P – BLOCK ELEMENTS – 19

1) Of the following statements which are true for NO2 ? a) A,B b) A,B,C c) B,C d) None 2) H3PO2 is the formula for one of the phosphorus acids. Its name and basicity are respectively. a) Phosphorus acid and two b) Hypophosphorus acid and two c) Hypophosphorus acid and one d) Hypophosphoric acid and …

P – BLOCK ELEMENTS – 20

1) Consider the isoelectronic series K+, S2-, Cl– and Ca2+. The radii of the ions decrease in the order a) b) c) d) 2) The oxygen molecule shows a) Paramagnetism b) Diamagnetism c) Ferromagnetlsm d) Ferrimagnetism 3) The element of group 16 that behaves as a typical metal is a) Sulphur b) Selenium c) Tellurium …

P – BLOCK ELEMENTS – 17

1) Which variety of glass is heat resistant? a) Bottle glass b) Pyrex glass c) Flint glass d) All 2) Borosilicate glass has the special property of being a) Resistant to heat b) Tough c) Transparent d) Uncrackable 3) A purple colour is imparted to glass by a) CoO b) c) d) 4) Which variety …

P – BLOCK ELEMENTS – 16

1) The melting point is highest in the case of. a) Pb b) Si c) Sn d) C 2) Thermodynamically the most stable form of carbon is a) Diamond b) Charcoal c) Graphite d) All are correct 3) Lead is most readily soluble in. a) Acetic acid b) Sulphuric acid c) Carbonic acid d) Hydrochloric …

P – BLOCK ELEMENTS – 15

1) Which of the following statements is not correct? a) Diborane has two three centred B-H-B bonds b) Tetraborane has four three centred B-H-B bonds and one B-B bond c) Diborane has one three centred B-H-B bond d) 2) Which of the following statements regarding borax is correct ? a) It is used in the …