Is it permissible to raise one's hands during supplication, whether that be in graveyards after burying the deceased, or on Friday after the second sermon has concluded?

Raising the hands during supplication (du'a) is legislated. It is part of the Sunnah for the Imam's sermon (khutbah) to include a supplication for the Muslims, encompassing the good of this world and the Hereafter, following the example of the Prophet, peace and blessings be upon him. The Imams of the Muslims have always done this. Ammarah ibn Ruwaybah al-Sulami, however, disapproved of raising the hands during supplication in the sermon, citing that the Prophet, peace and blessings be upon him, would raise only his index finger when supplicating during the sermon. It is recommended for the congregants (ma'mumeen) to say "Ameen" to the Imam's supplication.