Firstly: Hadath in Prayer Breaking one’s wudu’ intentionally
If one intentionally breaks their wudu’ in prayer, both their purity and prayer are invalidated. Prayer is reinitiated after purification. Consensus on this was related by Ibn Rushd, al-Nawawi, and al-Ramli. Involuntarily breaking one’s wudu’
If one involuntarily breaks their wudu’ in prayer, both their purity and prayer are invalidated. Prayer is reinitiated after purification. This is the position of the Shafi`is, Hanbalis, Ibn Baz, and Ibn `Uthaymin.
Secondly: Turning Away from the Qiblah in Prayer
If one turns away from the qiblah intentionally without valid cause, their prayer is invalid. Consensus on this was related by Ibn Hazm and Ibn Taymiyyah.
Thirdly: Non-Performance of an Integral of Prayer
If one intentionally misses an integral of prayer, their prayer is invalid. Consensus on this was related by al-Nawawi.
Fourthly: Speaking in Prayer
If one intentionally speaks in prayer, knowing that it is prohibited – without it being in the interest of the prayer, to save a Muslim, or something else that obliges him to speak – then his prayer is invalid. Consensus on this was related by Ibn al-Mundhir, Ibn `Abd al-Barr, Ibn Qudamah, Ibn Taymiyyah, and Ibn Hajar.
Fifthly: Laughing and Guffawing in Prayer
Laughing and guffawing invalidate prayer. Consensus on this was related by Ibn al-Mundhir, Ibn Hazm, Ibn Rushd, and al-Zayla`i.
Sixthly: Intentional Moving a Lot Without Necessity
It is not permissible to move a lot in prayer in ways that have not been commanded. The prayer is invalidated when this is intentional and without a valid reason. Consensus on this has been related by Ibn Battal, Ibn Hazm, Ibn `Abd al-Barr, and Ibn Taymiyyah.
Seventhly: Walking in Prayer
A large amount of walking invalidates the prayer. This is generally true.  Some scholars are of the opinion that a lot of movement does not invalidate prayer as long as the movement is allowed according to the Sharia, such as walking to stop someone from passing between one’s place of prayer and the qiblah. Consensus on this has been related by Ibn Battal and Ibn Hajar.
Eighthly: Intentionally Eating and Drinking in Prayer
Eating and drinking in prayer intentionally invalidates the prayer. Consensus on this has been related by Ibn al-Mundhir, Ibn Hazm, Ibn `Abd al-Barr, Ibn Qudamah, and Ibn Muflih.
The Ruling of Eating and Drinking Forgetfully or Ignorantly in Prayer
If one eats or drinks in a wajib or additional prayer – forgetfully or ignorant of the prohibition – does not invalidate the prayer if it is a small amount. However if it is a lot, it invalidates the prayer. This is the position of Shafi`is,  They hold that small and large amounts are known through customarily accepted practice. Hanbalis, and Ibn `Uthaymin.