Conditions for the validity of Salaah

Q: If a person prays with his t-shirt inserted in his pants, is his prayer valid or should he repeat it?

Q: I would like to confirm if the following is correct: 

1. Someone told me that when reading salaah, when facing the qibla, if you are a few degrees wrong then it is maaf.

2. If someone is reading salaah facing the wrong direction then you must turn them towards the right direction or tell them and they can turn to the right direction without breaking their salaah and their salaah will be accepted. 

Q: If you are in a hurry, can you pray your fardh while the azaan is happening or do you have to wait for the azaan to finish, and then pray your fardh?

Q: Is it permissible to offer salaah before azaan when the time of the prayer has begun?

Q: What is the duration of zawaal, sunrise and sunset?

Q: Please provide guidance on Salaah times.

1. I notice that some timetables stipulate Asr (Shafi) and Asr (Hanafi). There is usually a 70 minute difference between the 2 times.

1a. As I am Hanafi, what happens if I perform Asr at the time permitted for Shafi’s?

1b. At what time does Zuhr end, and Asr begin?

1c. As I am Hanafi, can I still read Zohr at the time that Asr for the Shafi’s commence?

2. Until what time can I perform Asr?

3. Until what time can I perform Maghrib?

4. Until what time can I perform Esha?

Q: I work in a hospital. The hand rub we use contains alcohol (ethanol) mixed with glycerine. Some drops fell on my clothes and dried. Can I pray with that clothes?

Q: Is wearing a skull cap mandatory whilst praying Salaah?

Q: I had offered 2 rakaahs of sunnah after zuhr, but I forgot that I already offered it. So I offered it again, but I mistakenly faced the wrong direction instead of the Qiblah. Should I offer the sunnah again?

Q: Till what time can one offer fajr prayer?