Is supplication immediately after the obligatory Salah (Prayer)
an act of Sunnah? Should we raise our hands during supplication? Which is better to raise the hands as the Imam does or not?
Offering supplications after obligatory Salah is not an act of Sunnah whether this is done by raising the hands of the Imam alone, the Ma'mum (a person being led by an Imam in Prayer) alone or both of them. Rather it is an act of Bid`ah (innovation in religion) because it was not reported from the Prophet (peace be upon him) or his Companions (may Allah be pleased with them). As for supplications in other situations, there is no harm in this due to the Hadiths narrated to this effect. (Part No. 7; Page No. 104) May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.