Is Capital Punishment going too easy on rapists and acid attackers?

With the current two movies Mardaani 2 and Chhapaak being in limelight,  I think we can discuss this in Bollywood forum. Do you think Capital Punishment is going too easy on the rapists and acid attackers? These two are the most heinous crimes after murder which changes the lives of the victims forever. Killing off these monsters is going too easy on them. Shouldn't they be suffering for their whole life just like the victims are suffering?