Which one of the following elements on doping with germanium, mak

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 Multiple Choice QuestionsMultiple Choice Questions

41.

Which one of the following is a correct set?

  • Diamond, sp2

  • Graphite, sp3

  • Diamond, sp

  • Graphite, sp2


42.

Diborane reacts with HCl in the presence of AlCl3 and liberates

  • H2

  • Cl2

  • BCl3

  • Cl2 and BCl3


43.

How many corners of SiO4 units are shared in the formation of three dimensional silicates?

  • 3

  • 2

  • 4

  • 1


44.

What is Z in the following reactions ?

BCl3+ H2 450°CCu-Al X + HCl X methylation Z

  • (CH3)BH2

  • (CH3)4B2H2

  • (CH3)3B2H3

  • (CH3)6B2


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45.

Which one of the following elements on doping with germanium, make it a p-type semiconductor?

  • Boron

  • Selenium

  • Arsenic

  • Germanium


A.

Boron

The group 13 elements have 1 electron short to Ge, thus giving rise to electron deficient bond or a hole which is responsible for electrical conductivity. Thus, group 13 elements (like Ga) on dopping with Ge, make it p-type semiconductor. Here p-type specifies that conduction is through positive holes in them.


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46.

Which one of the following elements reacts with steam?

  • C

  • Ge

  • Si

  • Sn


47.

Pure silicon doped with phosphorus is

  • amorphous

  • p-type semiconductor

  • n-type semiconductor

  • insulator


48.

Which one of the following correctly represents the variation of electronegatrvity (EN) with atomic number (Z) of group 13 elements?


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49.

Al3+, Fe3+, Zn2+ and Ni2+ ions are present in an acidic solution. Excess of ammonium chloride solution followed by addition of ammonium hydroxide solution. The available precipitate will contain

  • Zn(OH)2 and Ni(OH)2

  • Al(OH)2 and Fe(OH)3

  • Zn(OH)2 and Al(OH)3

  • Ni(OH)2 and Fe(OH)3


50.

Element showing the phenomenon of allotropy is

  • aluminium

  • tin

  • lead

  • copper


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