Asalamualaikum, can we recite Surah Al Asr in 1st rakat and Al Kafiroon in 2nd rakat of farz salah? Can we recite Sura An Nas in the 1st and Al Kausar in the 2nd rakat of farz salah?
In the name of Allah, the most Beneficent, the most Merciful.
According to the Hanafi Fiqh, reciting the Surahs in the order that they are in the Qur’an is necessary (wajib) inside the five daily obligatory prayers, the Jummah prayer, the Witr prayer and the Eid prayer. Reciting the Surahs in a reversed order deliberately is considered to be Makruh Tahrimi in these prayers, although it is not disliked in Nafl prayers. (Fatawa Mahmoodiyah p.227 v.10)
Therefore, with regards to your question it will be disliked to read Surah Naas in the first rakaat and Surah Kauthar in the second.
With regards to reading Surah Asr in the first rakaat and Surah Kaafiroon, the jurists have said that to make the second rakaat of any obligatory prayer longer than the first by reading more than two verses is disliked. However, the same rule does not apply for the optional prayers. Therefore, as Surah Kaafiroon has six verses and Surah Asr three, if you read it in the obligatory prayer it will be disliked and it will be permissible if you read it in the optional prayer. (Maraqi Falah p.96)
Only Allah Knows Best
Mohammed Tosir Miah
Darul Ifta Birmingham