There is no verse in the Quran which says Stoning of the Devil is part of the Hajj (Pilgrimage).
According to hadiths, the positions of the three pillars are supposed to be the places from where Devil tried to tempt and misguide Prophet Abraham three times into disobeying Allah Almighty by dissuading Abraham from carrying out Allah’s order.
But each time Prophet Abraham felt the presence of the devil trying to lure him, Angel Jibril told him to respond by throwing a stone (or stones) at Devil. Thus, the Devil failed to distract Abraham. It is said that the location of the three pillars at Mina where Devil stood, attempting to mislead Abraham.
For this reason pilgrims throw stones on the pillars. The pillars represent the places where Devil stood. Therefore, the purpose of throwing stones on the pillars is to express our contempt for the Devil where he was once said to have stood.
Keep in mind that this story and ritual is not contained in the Quran. It has its origin some other non-Quranic source.
All the correct rituals of Hajj are mentioned in the Quran, yet the stoning is not a Quranic ritual of Hajj (read surah Al-Baqara chapter2)
1- The devil is made of fire and thus cannot be touched by physical matter .
2- The devil is not sitting and waiting for to be stoned!