Q. What is the order of reciting surahs in fard and sunnah namaz? Will the sunna namaz be in order if one read a longer surah in 3rd rakat than the surah recited in 2nd rakat. What if one does the same in 2nd rakat of fard unintentionally?
A. The order of reciting Surahs in salaah is that the longest recitation be done in the first rakaat, then less longer in the second, then less longer in the third and then the shortest in the fourth in the sunnah salaah. In the fardh salaah, the recitation in the first rakaat should be longer than the second rakaat. In the case of Dhuhr salaah (fard), both the first and second rakaats can be the same duration (length). If however, this order is not maintained, and shorter surahs / qirat are read in the first rakaats while longer ones in the second rakaats, then salaah will be valid, but this will be Makrooh (reprehensible).
As such, the sunnah namaz will be in order if one reads a longer surah in the 3rd rakaat than the surah recited in the 2nd rakaat. The fard salaah will also be valid if the longer surah was read in the 2nd rakaat (of fard). However, as mentioned before, this will be Makrooh.
And Allah knows best.
Mufti Waseem Khan