Permanent hardness in water is hardness due to the presence of the chlorides, nitrates and sulphates of calcium and magnesium, which will not be precipitated by boiling. The lime scale can build up on the inside of the pipe restricting the flow of water or causing a blockage.

Antioxidants are additives capable of delaying or preventing rancidity of food due to oxidation, and therefore, lengthen the shelf life of products. They are very important in the food industry because they allow foods to conserve their nutritional properties and their quality levels. Antioxidants do not improve the quality of food, but it does help them to keep for a longer period of time. There is a wide variety of antioxidants from natural and synthetic origin, which are usually used in food. The most common uses of antioxidants are oils, margarines, confectionery, baked goods, pastries, snacks, cereals and sauces. Some natural antioxidants used in the food industry are Tocopherols, Ascorbic Acid or Rosemary Extract.

Soap is a mixture of sodium salts of various naturally occurring fatty acids. Air bubbles added to a molten soap will decrease the density of the soap and thus it will float on water. If the fatty acid salt has potassium rather than sodium, a softer lather is the result. Soap is produced by a saponification or basic hydrolysis reaction of a fat or oil. Currently, sodium carbonate or sodium hydroxide is used to neutralize the fatty acid and convert it to the salt.
General overall hydrolysis reaction:
fat + NaOH →glycerol + sodium salt of fatty acid
 

The correct answer is option C
Saccharin is the first popular artificial sweetener. It has been used as a sweetening agent ever since it was discovered in 1879. It is about 550 times as sweet as cane.

The correct answer is Option B.
Potassium soaps are softer to the skin than sodium soaps. These can be prepared by using potassium hydroxide solution in place of sodium hydroxide.
Potassium soaps are used in shampoo, shaving cream and bathing soaps etc sodium soaps are toilet soaps used for washing purposes.
 

The correct answer is option  C.
Pickling is a method of preserving food in an edible, antimicrobial liquid.In chemical pickling, the food is placed in an edible liquid that inhibits or kills bacteria and other microorganisms. Typical pickling agents include brine (high in salt), vinegar, alcohol, and vegetable oil.

The correct answer is Option B.
Glycerol is the residual product in the formation of soap. The immediate product is called an orthoester.
 

The correct answer is Option D.
When stearic acid reacts with polyethylene glycol non-ionic detergent is formed. 
Detergents which do not contain any ion in their constitution are non-ionic detergents.
CH₃ (CH₂ )₁₆ COOH + HO(CH₂ CH₂ O)nCH₂ CH₂ OH  ----H₂ O --->CH₃ (CH₂ )₁₆ COO(CH₂ CH₂ O)nCH₂ CH₂ OH

Tranquilizers and analgesics are neurologically active drugs. These affect the message transfer mechanism from nerve to receptor. Tranquilizers are a class of chemical compounds used for the treatment of stress, and mild or even severe mental diseases.