Salaah

Q: It is understood that performing Salaah/Sajdah in a place with najaasat is impermissible, with or without Prayer mat. But, I have witnessed many Muslims offering Salaah on the floor at offices, at railway stations, inside the aircraft, in trains, on the roads, on the deck of a ship/boat, etc. These places are frequented by many people returning from the toilets with their footwear on, which has a lot of najaasat. Will Salaah not be invalid for those who pray at these places with najaasat? I have had many debates with these people who justify that their Salaah is valid in these places.

Q: Following your question regarding making qadha of a fajr salaah started before sunrise but went over sunrise time whilst in salaah, what would one do if it is at a non makrook time? I.e. Asar beginning is at 3pm. One started zohr at 2.58 and finished at 3.05pm? What should one do and what is the condition of his salah?

Q: I have short term memory problem when I am praying salah. Sometimes I don't know how many rakat (rakah) I did, what shall I do then? I always don't know how many sajdah I did. If I did 1 or 2 sajdahs I don't remember. If I do more than 2 sajdah or do less than 2 sajdah would my salah be valid? I don't know if the cause of my problem is shaytaan. If I don't know how many rakaats and sajdah I did, what can I do? If I don't know, can I just do 1 more rakat or 1 more sajdah?​

Q: I have a problem reciting a certain part of the Tahiyyaat in Tashahhud. The part is: "...wa alaa ibadillaah'is salihin.." I have trouble pronouncing the last letter "n" out. Is it also permissible to read that part as: "...wa alaa ibaadillaah as salihin.." ? Thus "ibaadillaah" and "as" seperately, instead of connected as "ibaadillaah`is"?