Question

Detergents do not give scum with hard water.
State whether the given statement is true or false.
A.True
B.False

Answer 1

Hint: Detergents are not like soaps. They work well even with hard water and are more effective than soaps. When soap dissolves in hard water a solid like thing which is known as scum forms due to the reaction of calcium and magnesium salts present in the hard water.

Complete step by step answer:
We should first understand that detergents work in a very different manner when compared with soaps. Soaps are mainly formed by a process known as saponification. By interacting with it, these ions react with the activity of soap to form a grey, slimy material called soap scum.
So, what are these detergents? Detergents are substances that act in the water by softening it. It reduces the surface tension of water by acting as surfactants. They contain certain substances in them which reduces the surface tension of water.
But how is this possible? Detergents contain sodium carbonate $ (NaC{O_3}) $ which has the power to remove calcium and magnesium ions in the hard water. When this $ NaC{O_3} $ dissolves in water it gets split into $ Na $ and $ C{O_3} $ . This $ C{O_3} $ reacts with $ Ca $ and $ Mg $ ions to form calcium carbonate $ (CaC{O_3}) $ and magnesium carbonate $ (MgC{O_3}) $ . As a result the hard water gets softened and detergents don't form any scum in hard water.
So, for this question, the given statement is false.

Note:
There are mainly three types of detergents; Anionic detergents, Cationic detergents and Non- ionic detergents based on the types of ions present in them. Detergents have some disadvantages. If their hydrocarbon chain is highly branched, then bacteria cannot degrade it easily and thus cause environmental pollution and is harmful to nature.