How many different structures (configurations) are possible for the formula C2H5ClO (chloroethanol)?
Chloroethanol has the chemical formula of C2H5ClO. It consists of two central carbon atoms bonded together with a single bond and one chlorine substituent and one hydroxyl (OH) substituent. There are two different possible structures for chloroethanol. One is called 1-chloroethanol. The chemical formula is CH3-CHCl(OH). The chlorine atom and the hydroxyl oxygen are both attached to the same carbon. The second structure is called 2-chloroethanol. The chemical formula is CH2Cl-CH2OH. The chlorine atom and the hydroxyl oxygen are on two different carbons. Both of these structures are separate chemicals, each with separate physical properties such as boiling point and refractive index. These are the only two possible structures for chloroethanol.
I think I see the problem here. You referred to C2H5OCl as chloroethanol in your question because it is listed as such in that structure drawing activity. But at the question at the end which is what you posted they do not refer to the formula as chloroethanol by name. If we are not bound by the ethanol designation, there is one additional structure. The third structure is called chloromethyl methyl ether and the formula is CH3-O-CH2Cl. The oxygen atom is inbetween the two carbons.