Yes, in fact, all true soaps are made using a lye solution (sodium hydroxide mixed with a liquid). Soap is created when lye is mixed with oils and butters causing a chemical reaction called saponification. While all real soap must be made with lye, no lye remains in the finished product after saponification. You will notice that ingredients' lists differ depending on the manufacturers. Some will include the terms sodium hydroxide or lye, while others will use the term "saponified + the oil", which in essence means that sodium hydroxide was used to make the soap.
Products that contain water, such as body lotions and shampoos, for example, do have preservatives in them. Preservatives prevent bacteria and mold from growing. The preservatives used vary depending on the product, some may be naturally derived, while others are synthetically produced. We encourage you to read the ingredients lists.