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UNIT P block elements Sub groups 13, 14, 15, 16, 17 1. The electronic configuration of thallium is (a) (Ar) 3d10 4s2 4p1 (b) (Kr) 4d10 5s2 5p1 (c) (Xe) 5d10 6s2 6p1 (d) none of these Gillium and Indium follow (a) 1st transition series (b) 2nd transition series (c) 1st and 2nd transition series (d) 3rd transition series Thallium show variable valency or different oxidation states because (a) it is a d-block elements (b) it is a f-block elements (c) of its amphoteric nature (d) of inert pair effect Which of the following oxides is more stable than the other ? (a) Tl2O3 (b) Tl2O (c) Ga2O (d) In2O Gallium and Indium are used to dope germanium to produce (a) intrinsic semiconductors (b) p-type semiconductors (c) n-type semiconductors (d) non-conducting Ge A silvery white metal is solid in cold days but liquefies on hot day, and reacts with dilute Hcl to (a) Sn (b) Sb (c) Bi (d) Ga Borax has the formula (a) Na2B4O7.10H2O (b) H3BO3 (c) NaBO2 (d) Na3BO3 When borax is heated with Cobalt nitrate, a blue bead is formed. The bead consists of (a) Cobalt meta-borate (b) Sodium meta-borate +Cobalt oxide (c) CoO + B2O3 (d) CoO + Na2B4O7 Which metal is usually obtained from its ore by electrolytic reduction? (a) Fe (b) Pb (c) Su (d) Al 10. Al. is a self - protecting metal because (a) it never tarnishes (b) it develops a carbonate Coating (c) it develops an oxide coating (d) it is inert 11. The reducing agent used in thermite process is (a) Fe2O3 (b) Fe (c) Al2O3 (d) Al 12. The basis for Al as a reducing agent in thermite process is (a) high exothermic H hydration of Al3+ (b) high Eox. Pot. of Al (c) high exothermic enthalpy of formation of Al2O3 (d) high I.E. of Al 13. Which of the following will not rapidly attack and destroy a pure Alumiium can ? (a) NaOH Solution (b) Na2CO3 (c) Conc. HNO3 (d) Conc. HCl 14. which one of the following will produces an acidic solution in water ? give H2. It can be (a) Al2(SO4)3 (b) K2SO4 (c) NaHCO3 (d) Na2CO3 15. Which aluminium compound is most likely to contain the Al3+ ion ? (a) oxide (b) fluoride (c) Chloride (d) phosphide 16. Boron nitride (BN) can be best prepared by (a) 2B + N2 1800 2BN C (b) B2O3 + 3C + N2 1800 2BN C (c) B2 O3 + N2 1800 2BN C burn (d) B + air BN
2.
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6.
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17. Of the follwoing Lewis acids, which one has triangular planer geometry and has zero dipole moment ? (a) BF3 (b) AlF3 (c) GaF3 (d) TlF3 18. A solution of borax in water is (a) acidic (b) alkaline (c) neutral (d) none of these 19. Rection of dil. H2SO4 with borax produces (a) H3BO3 (b) HBO2 (c) H4B2O7 (d) B2O3 20. Diborane can be prepared by the reactions (a) 4bcl3 + 3LiAlH4 2B2H6 + 3LiCl + AlCl3 (b) 6LiH + 2BF3 6LiF + B2H6 (c) Mg3B2 + 6H2O 3Mg(OH)2 + B2H6 (d) all of these 21. Diborane has the structure: H H H (a)
(d) Ph - C - Ph Ph - CHOH - PH
|| O
23. The reaction of LiH with AlCl3 produces (a) Al2 Cl6 (b) AlH3 (c) LiAlH4 (d) LiCl 24. The molecule B3N3H6 is (a) iso-electronic with benzene (b) called inorganic benzene (c) borazole (d) all of the above 25. What is not correct for boron ? (a) pure boron is made by reducing BBr3 with H2 gas as a hot tantalum filament (b) Boron is very hard, high melting, semiconducting solid (c) Boron is used to make control rods for nuclear reactor (d) Boron has a tetrahedral slimclire Hint: Boron is B12 icosahedron - 12 Boron atoms at the corners 26. The halides of IIIA group elementsare (a) lewis acids (b) lewis bases (c) Bronsted acids (d) Arrhenius acids 27. Which of the following process is not used for purification of bauxite ? (a) Baeyers process (b) Hall's Process (c) Hall's Process (d) Hope's process 28. Next to diamond, the substance hardest is (a) AIN (b) B4C3 (c) BN (d) B4C 29. The halide of Al which sublimes on heating is (a) AlF3 (b) AlBr3 (c) AlCl3 (d) AlI3 30. Spectroscopic and nuclear magnetic reasonance studies shwo that in B2H6 (a) all the six hydrogen are like ethylene
B H
H
B H
H B H H
H
(b) H
B H
H
(c)
H B B H H H
H
H
(d)
H B B H
H H
H
22. Diborane reacts with NaH to give a reducing agent which performs selective reduction (a) CH3 CH = CH CHO CH3 CH2 CH2 CH2OH (b) CH3 CH = CH CHO CH3 CH CH3 CH = CH2OH (c) C6H5CHO C6H5CH2OH
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(b) two hydrogens are of one type and four of another type (c) 3 hydrogens are of one type and three of another type (d) none of these 31. Which of the following is not as alum? (a) K2SO4.Al2 (SO4)3.24H2O (b) K2SO4.Cr2 (SO4)3.24H2O (c) K2SO4.Fe2 (SO4)3.24H2O (d) FeSO4.(NH4)26H2O 32. The blue coloured mineral "Lapis Lazuli" used as precious stone is essentially (a) Sodium aluminium silicate (b) Zinc Cobalate (c) Boric copper carbonate (d) Cobalt meta borate 33. Which of the following properties of Al are not typical of most other metals ? (a) considerable temperature difference between M.P. and B.P. (b) negative standard electrode potential (c) electrical resistance increases with increase in temperature (d) forms salts with alkalies 34. Which of the following statements concerning Al2O3 is not wholly correct ? (a) it is formed together with some nitride when Al is heated in air (b) it is amphoteric, but its acidic properties are more prominent (c) it has high exothermic enthalpy of formation (d) it forms salts with NaOH 35. Which one of the following, statements about group III element, B to Tl, is incorrect ? (a) all exhibit oxidation state of +3 (b) all form oxides of the formula M2O3 (c) all form trihalide, MX3 (d) all form amphoteric hydroxides, M(OH)3 36. B3+ ion is unknown because of (a) high 1st, 2nd and 3rd I.E. (b) H lattice is less than sum of three I.E. (c) DH hydration is less than sum of three I.E. (d) all of the above 37. Which of the following compound does not exist ? (a) TlF3
(b) TlCl3 (c) TlBr3 (d) TlI3 38. Boron resembles silicon in the facts except (a) bothe are non-metals which have seciconducting properties (b) B2O3 and SiO2 are acidic (c) B2H6 and Si2H6 are covalent gases which are hydroalyzed (d) Bcl3 and SiCl4 are Lewis acids 39. B3+ ion does not exist in ionic salts or in solution because (a) H lattice is less than H sub + H I.E. (b) H hyd. is less than H sub + H.I.E. (c) both of the above (d) none of above 40. The stability of +3 oxidation state in aqueous solution is in order: (a) Al > Ga > In >Tl (b) Tl > In > Ga > Al (c) Al > Tl > Ga > In (d) Tl > Al > Ga > In 41. In the reaction 2NaH + B2H6 2Na+ (BH4), (BH4) ion has which geometry ? (a) planer (b) pyramidal (c) tetahedral (d) Square planar 42. Inorganic graphite, BN, (a) has graphite like layer structures (b) has sp2 hybrid orbitals an each B and N (c) is a white refractory solid (d) all of these 43. Inorganic Benzene, B3N3H6, borazole (a) resembles C6H6 in M.P. and B.P. (b) is iso-electronic with benzene (c) has a cyclic structure (d) all of these 44. Alzheirmer's disease is due to (a) deposits of Al - salts in the brain (b) deposits of Cu - salts in the brain (c) Na+ and K+ ions imblance (d) ingestion of thallium salts 45. Gallium arsenide (Ga - As) is (a) iso-electronic with germanium (b) used in laser diodes (c) used to make memory chips for computers (d) all the above
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QUEST TUTORIALS Head Office : E-16/289, Sector-8, Rohini, New Delhi, Ph. 65395439