Assalamu Alaikum What is the ruling on some reciters pronouncing the letter ḍād as ẓā?

There is no sin upon one who cannot distinguish between the letters ḍād (ض) and ẓāʾ (ظ). However, for one who is able to learn and distinguish, it is obligatory upon them to do so, and they would be sinful for neglecting it. Nevertheless, their prayer is not invalidated unless they intentionally mispronounce while being capable of correct pronunciation. Many scholars are of the opinion that their prayer is not invalidated, even if distinguishing between them is difficult. Imam Ar-Ramli holds that substituting ḍād with ẓāʾ invalidates the prayer if it occurs in Al-Fatihah or what stands in its place, and if done by one who is capable, knowledgeable, and intentional. The correct view among scholars is that mixing ḍād and ẓāʾ is excusable due to the proximity of their articulation points and the similarity of their characteristics. As for the hadith (definition), "I am the most eloquent of those who spoke with the ḍād," it has no basis.