Question

Statement: Detergents give scum with hard water.

State whether the given statement is true or false.

• A. True
• B. False

Answer 1

The correct option is B False

Detergents are not soaps. Detergents work by coming in contact with a surface and reducing surface tension, with something known as a surfactant. Basically allowing the dirt to slide away. Detergents are synthetics. Soap is natural, like glycerine or tallow.But they are very active in hard water.
One reason why laundry detergents work better than soap is that they contain substances that soften the water. Hard water contains dissolved calcium $C{a}^{+2}$ and magnesium $M{g}^{+2}$ ions. These ions interfere with the action of soap by reacting with it to form a gray, slimy substance called curd or soap scum. Laundry detergents inhibit curd formation because they contain substances such as sodium carbonate $\left(NaC{O}_3\right)$ that removes the Ca and Mg ions from the water. When sodium carbonate dissolves in water it separates to form Na ions and $C{O}_3$ ions. The dissolved $C{O}_3$ ions react with the Ca and Mg to form $CaC{O}_3$ and $MgC{O}_3$ which are solids and settle to the bottom of the washer. Hence given statement is false because it given scum even in soft water but not that much.