Patients with < 10% TBSA burns can be resuscitated orally (unless the patient has an electrical injury or associated trauma). In the case of patients with burns 10-40% TBSA, secure a large-bore IV line; add a second line if transportation will take longer than 45 minutes. South African Burn Society burn stabilisation protocol
Water is an ingredient that can dissolve soap. Water is a solvent and the the soap is the solute. Solutes are things that dissolve in solvents. I'm not sure what you're asking about an ingredient, but water makes all soap dissolve.
The sodium lauryl sulfate found in our soaps is exactly the same as you would find in a car wash or even a garage, where it is used to degrease car engines. In the same way as it dissolves the grease on car engines, sodium lauryl sulfate also dissolves the oils on your skin, which can cause a drying effect. It is also well documented that it denatures skin proteins, which causes not only irritation, but also allows environmental contaminants easier access to the lower, sensitive layers of the skin.