A detergent is a surfactant or a mixture of surfactants with "cleaning properties in dilute solutions. These substances are usually alkyl benzene suffocates, a family of compounds that are similar to soap but are more soluble in hard water, because the polar sulfonate (of detergents) is less likely than the polar carboxyl (of soap) to bind to calcium and other ions found in hard water. detergents are also foaming agents to varying degrees.