Reaction of silicon with acids
Silicon does not react with most acids, under normal conditions. It is dissolved by hydrofluoric acid, HF, most likely due to the complex formation of [SiF6]2−, as the driving force.
Si(s) + 6 HF(aq) [SiF6]2−(aq) + 2H+(aq) + 2 H2(g)
Reaction of silicon with air
Silicon is passivated by a thin layer of SiO2 on the surface, and does not otherwise react with air under normal conditions.
If heated above 900 °C, silicon reacts with the oxygen, O2, forming SiO2:
Si(s) + O2(g) SiO2(s)
If heated above 1400 °C, silicon reacts with the nitrogen, N2, forming the silicon nitrides SiN and Si3N4:
2 Si(s) + N2(g) 2 SiN(s)
3 Si(s) + 2 N2(g) Si3N4(s)
Reaction of silicon with bases
Silicon reacts with hot alkali solutions, forming silicate ions, SiO32− :
Si(s) + 2 OH−(aq) SiO32−(aq) + 2 H2(g)
Reaction of silicon with halogens
Silicon reacts halogens, forming the corresponding Si(IV) halides.
Si(s) + 2 F2(g) SiF4(g) 
Si(s) + 2 Cl2(g) SiCl4(l) 
Si(s) + 2 Br2(g) SiBr4(l)
Si(s) + 2 I2(g) SiI4(s)
Reaction of silicon with water
Silicon does not react with water, even as steam, under normal conditions.
Method 4500-Si G Inductively Coupled Plasma Method . A portion of the sample is digested in a combination of acids. The digest is aspirated into an 8,000 K argon plasma where resulting light emission is quantified for 30 elements simultaneously.
Method limit of detection in water = 0.05 mg/L