Which one of the following is a correct set?
Diamond, sp2
Graphite, sp3
Diamond, sp
Graphite, sp2
How many corners of SiO4 units are shared in the formation of three dimensional silicates?
3
2
4
1
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.
Pure silicon doped with phosphorus is
amorphous
p-type semiconductor
n-type semiconductor
insulator
Which one of the following correctly represents the variation of electronegatrvity (EN) with atomic number (Z) of group 13 elements?
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