Coconut oil upon hydrolysis with potassium hydroxide gives :
- A.Free fatty acids and sodium hydroxide
- B.Glycerol and sodium salts of fatty acids
- C.Glycol and potassium salts of fatty acids
- D.Glycerol and potassium salts of fatty acids
Correct answer
Explanation
The correct answer is D, Glycerol and potassium salts of fatty acids. Boiling an oil or fat with an alkali splits it into glycerol and the salts of its fatty acids; with potassium hydroxide those salts are potassium salts.
Coconut oil, like every vegetable oil, is a triglyceride: an ester of glycerol with three fatty acids. Its alkaline hydrolysis is called saponification because the potassium salts formed are soap. Potassium soaps are soft and are used in shaving creams and liquid soaps, while sodium hydroxide gives the hard sodium soaps of ordinary bathing bars.
A is wrong because an alkali does not leave free fatty acids, and no sodium is present in the reaction to give sodium hydroxide.
B is wrong because potassium hydroxide gives potassium salts, not sodium salts.
C is wrong because the alcohol released from a fat is glycerol (a triol), not glycol.
Exam tip: fat + alkali = glycerol + soap; NaOH gives hard soap, KOH gives soft soap.
Practice Questions
View allMarginal placentation, in which the ovules are borne along the fused margin of a single carpel, is found in
- A.Tomato
- B.Pea
- C.Mustard
- D.Sunflower
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The pea's ovary is made of one carpel whose two margins fuse to form a ridge, and the ovules are arranged in two rows along that ridge; this is marginal placentation, and it is why the pod opens to show a single row of seeds on each side.
Read the full explanation →Mango and coconut are examples of which type of fruit?
- A.Berry
- B.Drupe
- C.Pome
- D.Legume
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A drupe is a fleshy fruit with a thin epicarp, a mesocarp that may be pulpy as in the mango or fibrous as in the coconut, and a hard, stony endocarp enclosing a single seed; the coconut's shell is that endocarp and the white kernel is the seed.
Read the full explanation →The apple is regarded as a false fruit because
- A.It has no seeds
- B.It develops from the thalamus along with the ovary
- C.It develops without fertilisation
- D.Its pericarp is stony
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A true fruit forms from the ovary alone, but in the apple and the pear the thalamus grows, becomes fleshy and forms the greater part of the edible tissue, while the ovary makes only the core; such a fruit is called a false or spurious fruit, and the specific type…
Read the full explanation →Vexillary aestivation of the corolla is found in the flower of
- A.Pea
- B.Cotton
- C.Calotropis
- D.Gulmohar
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In vexillary or papilionaceous aestivation the corolla has five petals of unequal size: one large posterior petal, the standard, which covers two lateral wing petals, which in turn cover the two smallest anterior petals that are fused into a keel.
Read the full explanation →In a racemose inflorescence, the flowers are borne in
- A.Basipetal succession
- B.Acropetal succession
- C.A single terminal cluster
- D.No definite order
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In a racemose inflorescence the main axis does not end in a flower but keeps growing, so the lowest flower is the oldest and the youngest buds are at the tip; this upward order is called acropetal, as in radish, mustard and Larkspur.
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