Galena is
Zns
Pbs
CuFeS2
TnS
The fuel used in modern airships
Hydrogen
Helium
Argon
Nitrogen
Gypsum is
CaSO42H2O
2CaSO4H2O
CaSO4
CaCl2
The basic resource in chlor - alkali industry
Sodium chloride
Potassium chloride
Chlorine
The barium meal which is taken before an X - ray contains the salt
BaCl2
BaO2
BaSO4
Ba(OH)2
The sulphur compound used as a food preservative
SO2
SO3
H2SO4
H2S2O7
The solvent used to separate iodine molecules in the solid from each other
Water
Benzene
HCl
Cyclohexane
