What is the order of Fajr prayer with Sobh prayer in relation to the first and second calls to prayer, and does Fajr prayer ever become void during the day, and what is said in the Qunoot supplication?

Fajr prayer is the Dawn prayer, and its time is after the true dawn breaks. It has a Sunnah (definition) of two Rak'ahs (units of prayer) that precedes it, performed between the breaking of the true dawn and the Fajr prayer. The Sunnah is not valid before the true dawn breaks. If the Fajr prayer and its Sunnah are missed, the preponderant opinion is to perform the two Rak'ahs of the Sunnah before the obligatory (Fardh) prayer. It is recommended to make up the missed Fajr Sunnah either after the obligatory prayer or to delay it until after sunrise.