Ncert Exercises & Solutions

Q. 77 How can you obtain iodoethane from ethanol when no other iodine

containing reagent except Nal is available in the laboratory?

Ethanol is treated with red phosphorous and bromine mixture and the product formed will

be bromoethane. The bromoethane so formed is then treated with Nal to give iodoethane.

$C H_{3} C H_{2} O H \overset{R e d P / B r}{\to} C H_{3} C H_{2} B r$
$C H_{3} C H_{2} B r \overset{N a l}{\to} C H_{3} C H_{2} l + N a B r$

‘This reaction is known as Finkelstein reaction.