
Define hydrogenation?
Answer
493.5k+ views
Hint:Alkenes are readily hydrogenated under pressure in presence of a catalyst.
Alkene shows chain, position, functional (ring chain), optical & geometrical isomerism and undergo addition reactions due to unsaturation.
Complete answer:
The addition of hydrogen to an alkene or alkyne in presence of a catalyst to form a saturated hydrocarbon, alkane is called hydrogenation. The addition of hydrogen to form a saturated compound is termed hydrogenation.
The following catalysts have been used satisfactorily in the above reaction.
(i) Finely divided platinum and palladium are effective at room temperature. Platinum or palladium black i.e., metals in a very finely divided state, may be prepared by reducing their soluble salts with (formaldehyde).
(ii) Nickel requires a temperature of . Raney nickel is effective at room temperature. Platinum or and atmospheric pressure. (The method for the preparations of Raney nickel has been described elsewhere in the module).
One molecule of hydrogen is adsorbed for each double bond present in the unsaturated compound. The order of rate of hydrogenation of alkenes at room-temperature and atmospheric pressure is
or a ring double bond
Alkenes of the type are difficult to hydrogenate under the above reaction conditions.
Note:
Alkynes can be reduced directly to alkanes by the addition of in the presence of a catalyst. The addition reaction takes place in two steps. lt is not possible to isolate the mediate alkene under the above reaction conditions. By using Lindlar’s catalyst [Pd on ] nickel boride, alkynes can be partially hydrogenated to syn product.
Alkene shows chain, position, functional (ring chain), optical & geometrical isomerism and undergo addition reactions due to unsaturation.
Complete answer:
The addition of hydrogen to an alkene or alkyne in presence of a catalyst to form a saturated hydrocarbon, alkane is called hydrogenation. The addition of hydrogen to form a saturated compound is termed hydrogenation.
The following catalysts have been used satisfactorily in the above reaction.
(i) Finely divided platinum and palladium are effective at room temperature. Platinum or palladium black i.e., metals in a very finely divided state, may be prepared by reducing their soluble salts with (formaldehyde).
(ii) Nickel requires a temperature of
One molecule of hydrogen is adsorbed for each double bond present in the unsaturated compound. The order of rate of hydrogenation of alkenes at room-temperature and atmospheric pressure is
Alkenes of the type
Note:
Alkynes can be reduced directly to alkanes by the addition of
Recently Updated Pages
Master Class 11 Business Studies: Engaging Questions & Answers for Success

Master Class 11 Economics: Engaging Questions & Answers for Success

Master Class 11 Accountancy: Engaging Questions & Answers for Success

Master Class 11 Computer Science: Engaging Questions & Answers for Success

Master Class 11 English: Engaging Questions & Answers for Success

Master Class 11 Maths: Engaging Questions & Answers for Success

Trending doubts
The flightless birds Rhea Kiwi and Emu respectively class 11 biology CBSE

1 litre is equivalent to A 1000mL B 100cm3 C 10mL D class 11 physics CBSE

A car travels 100 km at a speed of 60 kmh and returns class 11 physics CBSE

Name the Largest and the Smallest Cell in the Human Body ?

Explain zero factorial class 11 maths CBSE

In tea plantations and hedge making gardeners trim class 11 biology CBSE
