Which of the following is a correct formula unit? pbcl alp li3al clo

 AIP  

There are two types of substances mixture and pure substance. Mixture has NO chemical formula and a pure substance has a chemical formula. There are two types of pure substances, elements (mono atomic and molecular) and compounds ( covalent and ionic).  

Ionic compounds do not exist in independent molecular form. They form three dimensional crystal lattice, in which each ion is surrounded by oppositely charged ion.  so the ratio of ion is called the formula unit  

i think it's c. i'm not sure but i think so.

> b takes place in the gas phase in an isothermal tubular reactor. the feed is one mole of a per one mole of c, an inert. the entering temperature and pressure are 427°c and 10 atm, respectively. the gas constant r = 0.08206 atm · l/mol · k.