Question

why soaps take more time to dissolve in water while detergents take less time...??????

Answer 1

Often we use the words "soap" and "detergent" interchangeably, but really they're quite different things. A detergent is a chemical substance you use to break up and remove grease and grime, while soap is simply one kind of detergent. Soap has a long history and was originally made from purely natural products like goat's fat and wood ash. Today, detergents are more likely to be a mixture of synthetic chemicals and additives cooked up in a huge chemical plant and, unlike traditional soap, they're generally liquids rather than solids. Detergents are used in everything from hair shampoo and clothes washing powder to shaving foam and stain removers. The most important ingredients in detergents are chemicals called surfactants—a word made from bits of the words surface active agents.

What are surfactants?

You might think water gets you wet—and it does. But it doesn't get you nearly as wet as it might. That's because it has something called surface tension. Water molecules prefer their own company so they tend to stick together in drops. When rain falls on a window, it doesn't wet the glass uniformly: instead, it sticks to the surface in distinct droplets that gravity pulls down in streaks. To make water wash better, we have to reduce its surface tension so it wets things more uniformly. And that's precisely what a surfactant does. The surfactants in detergents improve water's ability to wet things, spread over surfaces, and seep into dirty clothes fibers.

Surfactants do another important job too. One end of their molecule is attracted to water, while the other end is attracted to dirt and grease. So the surfactant molecules help water to get a hold of grease, break it up, and wash it away.