Question

$A\underset{\text{Catalyst}}{\overset{Lindla{r}^{\prime }s}{\leftarrow }}R-C\equiv C-R\stackrel{\text{Birch reduction}}{⟶}B$
Where, A and B are geometrical isomers $(R-CH=CH-R)$.
Choose the correct option from the following:

• A. A and B both are trans
• B. A is cis, B is trans
• C. A and B both are cis
• D. A is trans, B is cis

Answer 1

The correct option is B A is cis, B is trans

Birch reduction gives trans product and lindlar's catalyst gives cis. Hence correct option is (d).
Birch Reduction takes place in presence of $Na/liq.N{H}_3$
Lindlar's catalyst is $H_2,Pd/C$