The hardening of vegetable oil into vanaspati by passing hydrogen over a nickel catalyst is an example of
- A.Substitution reaction
- B.Addition reaction
- C.Displacement reaction
- D.Neutralisation reaction
Correct answer
Explanation
The correct answer is B, an addition reaction. Vegetable oils contain unsaturated chains with carbon to carbon double bonds; hydrogen adds across those double bonds in the presence of nickel or palladium, turning them into single bonds, so the oil becomes saturated and sets into a solid fat. Option A is wrong because a substitution reaction replaces one atom or group of a saturated compound with another, as when methane reacts with chlorine in sunlight, and nothing is replaced here. Option C is wrong because a displacement reaction is one in which a more reactive element pushes a less reactive one out of its compound, which describes reactions of metals rather than this one. Option D is wrong because neutralisation is the reaction of an acid with a base to give salt and water, and no acid or base takes part in hydrogenation.
Read the full article: Carbon and Its Compounds: Bonding, Allotropes and PYQs
Practice Questions
View allCooking gas (LPG) mainly consists of
- A.Ethene
- B.Ethyne
- C.Propene
- D.Propane and Butane
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Liquefied petroleum gas is a mixture of these two saturated hydrocarbons, which are gases at ordinary pressure but turn liquid under moderate pressure, so a large quantity of fuel fits into a small cylinder; a strong-smelling compound is added so that a leak is noticed.
Read the full explanation →How many isomers does C6H14 have?
- A.3
- B.6
- C.4
- D.5
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Hexane, C6H14, can be drawn as a straight chain of six carbons, as two chains of five carbons with a methyl branch in different positions, and as two chains of four carbons carrying branches, which gives five different structures with the same molecular formula.
Read the full explanation →Compounds with exactly two double carbon to carbon bonds are known as ______.
- A.Terpenes
- B.Dienes
- C.Trialkyne
- D.Dialkyne
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The prefix di stands for two and the ending ene for a carbon to carbon double bond, so a diene is a hydrocarbon carrying exactly two such bonds; buta-1,3-diene, the raw material of synthetic rubber, is the standard example.
Read the full explanation →The first member of the alkyne group of hydrocarbons is
- A.propyne
- B.ethyne
- C.methyne
- D.butyne
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An alkyne contains a carbon to carbon triple bond, which needs at least two carbon atoms, so the series begins with ethyne, C2H2, also called acetylene and used with oxygen in welding.
Read the full explanation →A gas stove flame burns blue because of
- A.Complete combustion of fuel
- B.Presence of hydrogen in the air
- C.Hazardous combustion
- D.Insufficient oxygen
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When enough air reaches the burner, every carbon atom of the fuel is oxidised fully to carbon dioxide and the flame is blue and hot, giving the maximum heat for the gas consumed.
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