Catalytic hydrogenation involves addition of hydrogen to a gt C = Clt or -C -= C- bond in presence of a metal catalyst such as Ni, Pt, Pd, etc. These are called heterogeneous catalysts. Both H_2 and alkene/alkyne get adsorbed on the surface of the metal , and syn-addition of hydrogen atoms takes place. The relative rates of hydrogenation follows the order: -C-=C- gt gt C=C lt gt C=o lt C_6H_6 If sodium or lithium in liquid ammonia is used, anti-addition of H-atoms occurs across -C-=C-bond. These reducing agents can also be used to reduce double bonds of benzene rings and conjugated dienes but not of isolated dienes. [A]underset"Catalyst"overset"Lindlar's"larrCH_3-C-=C-CH_3underset(liq. NH_3)overset" Na in"to [B] [A] and [ B] are respectively

Catalytic hydrogenation involves addition of hydrogen to a gt C = Clt

1.	Catalytic hydrogenation involves addition of hydrogen to a gt C = Clt or -C -= C- bond in presence of a metal catalyst such as Ni, Pt, Pd, etc. These are called heterogeneous catalysts. Both H_2 and alkene/alkyne get adsorbed on the surface of the metal , and syn-addition of hydrogen atoms takes place. The relative rates of hydrogenation follows the order: -C-=C- gt gt C=C lt gt C=o lt C_6H_6 If sodium or lithium in liquid ammonia is used, anti-addition of H-atoms occurs across -C-=C-bond. These reducing agents can also be used to reduce double bonds of benzene rings and conjugated dienes but not of isolated dienes. [A]underset"Catalyst"overset"Lindlar's"larrCH_3-C-=C-CH_3underset(liq. NH_3)overset" Na in"to [B] [A] and [ B] are respectively
Answer» cis, trans-2-butene both trans-2-butene trans,cis-2-butene both cis-2-butene Solution :Least SUBSTITUTED alkene has the MAXIMUM HEAT of HYDROGENATION, i.e., OPTION (d) is correct.