Question

Dalda is prepared from oils by:
A. Oxidation
B. Reduction
C. Hydrolysis
D. Distillation

Answer 1

Hint: We can say that esters of unsaturated fatty acids are oils and esters of saturated fatty acids are dalda. We can convert oil to dalda using catalytic hydrogenation. In the process of catalytic hydrogenation, we can use metal catalysts like palladium, platinum (or) nickel.

Complete step by step answer:
We know that the oils are entities that contain esters of unsaturated fatty acids and dalda is an entity that contains esters of saturated fatty acids. We can convert unsaturated fatty acids to saturated fatty acids by simple hydrogenation reaction. There are three major components in hydrogenation reaction. The first component is hydrogen, the second component is substrate, and the third component is catalysts. These three components are generally necessary to activate the reaction at temperatures and pressures which are lower. In several hydrogenation reactions, gaseous hydrogen is used as a source of hydrogen. The temperatures and pressures could also be varied based on the nature of the catalyst and substrate we are using. In catalytic hydrogenation we use catalysts such as platinum, palladium, rhodium for the binding of the hydrogen molecule and the catalyst activates the reaction between the substrate and the hydrogen.
The process of catalytic hydrogenation generally happens at lower pressures and lower temperatures. Nickel based catalyst like Raney nickel requires high pressures and high temperatures.
In the hydrogenation reaction of vegetable oils and fatty acids, energy of about 25kcal/mol is liberated and the reaction is an exothermic reaction. Hydrogenation and catalytic hydrogenation is a reduction reaction.

So, the correct answer is Option B.

Note: We have to know that the reverse of hydrogenation is dehydrogenation. The process of hydrogenation is different from addition of hydride (or) protonation because in the hydrogenation process the products contain the same charge as the reactants. If the hydrogenation reaction is incomplete, there would be significant implications in health.