Q.(a) What happens when SiO_2 is heated fused alkali NaOH ?

Silicon is a classic example of a semiconductor, a solid whose electrical conductivity lies between that of a conductor and an insulator.

This is one item from a five-way matching set (Column A: Silicon, K4[Fe(CN)6], Lucas reagent, Formic acid, Monosaccharides ↔ Column B: Reducing sugars, Semiconductor, Red ants, Conc. HCl and ZnCl2, Counter ions). Silicon is a metalloid whose conductivity, unlike a true metal, increases with temperature and can be tuned by 'doping' with small amounts of Group 13 or Group 15 elements (giving p-type or n-type semiconductors respectively) — this is why it pairs with 'Semiconductor'. This particular pairing is drawn from the Solid Sta …

Silicon is the classic semiconductor element, used to build diodes, transistors, and integrated circuits.

A semiconductor has electrical conductivity intermediate between a good conductor (like a metal) and an insulator, and - unlike a metal - its conductivity increases with temperature and can be finely controlled by adding trace impurities (doping with elements like boron or phosphorus). Silicon (and germanium) fit this description perfectly and are the backbone of the modern electronics industry. Carbon in its common allotropes (diamond is an in …