Question

In order to study the saponification reaction we first prepare 20% solution of sodium hydroxide. If we record the temperature of this solution just after adding sodium hydroxide flakes to water and also test its nature using litmus, it may be concluded that the process of making this solution is:
(A) Exothermic and the solution is alkaline
(B) Endothermic and the solution is alkaline
(C) Endothermic and the solution is acidic
(D) Exothermic and the solution is acidic

Answer 1

Hint: Saponification is a process that involves presence of sodium hydroxide that is NaOH. Fat, oil, liquid is converted into soap and alcohol along with the action of the heat. An Example of soap is sodium palmitate.

Complete Step by step solution:
Soaps are the salts of fatty acids. Fatty acids are mono that have long carbon chains. Traditional materials such as vegetable oils and animal fats are saponified. The other major method of saponification is reaction of fatty acids with the base. In this reaction, there is neutralization of carboxylic acid. This neutralization method helps us to produce industrial soaps. These industrial soaps are derived from magnesium, aluminium and transition metals. Also, depending upon the alkali used in the production of soap, the properties of the soap are distinct. Sodium hydroxide produces hard soap. By contrast, soft soaps contain potassium. Soft soaps are derived from potassium hydroxide.
Heat is liberated in the saponification reaction and hence it is an exothermic reaction. The solution of sodium hydroxide in water turns red litmus blue and hence the solution is alkaline.
Therefore, the correct answer is option A.

Note:
The soap formed due to the saponification reaction remains in the suspension form. Soap is precipitated from suspension form by adding common salt to the suspension. This occurs as salt reduces the solubility of soap and as a result it is precipitated out.