Those things which render the Salaah invalid

Q: What is the ruling on the person who lifts his feet of the ground during sajdah? Is his salaah invalidated?

Q:

1. Is it permissible to hold the Quran in one's hand in Salah for reading so that one can read unknown surahs after sure fateha.

2. Is it permissible to read the whole tarawih prayers (alone) and in other prayers.

3. If not, could you please tell me why we should not do it.

4. Why do people in the haram hold the Quran in their hand and read or read from the phone in their salah.

Q: While in sujood, can I make dua in my own language? For example, I ask Allah's help for my work, or ask for betterment for my family's health or ask for jannah? If yes then in nafl sujood only or even fard/sunnah?

Q: If your mucus/phlegm has become sweet because of something sweet you ate then will it be okay to pray in that condition? Like in Ramadan when everyone drinks milkshake and eats dates when they break their fast and then they just wash their mouth out with water and stand up for Maghrib Salah even though their mucus is still sweet and the back of their throat is still sweet. Sometimes your mucus remains pink even after you wash your mouth out. What happens if you swallow this pink mucus during salah? Is it sufficient to quickly rinse out your mouth with water before salah or should you wait until the sweet mucus goes away? Sometimes I only break fast with water then eat after I pray to avoid this problem. What is the best way to deal with this?

Q: In fajr farz on the last rakat I made a mistake and I believe I got kind of mad and smacked my lips in the salaah but then I fixed my mistake. Is this fine?

Q: If a person performed Salaah and a while after that realised that there was blood on his clothes and was not sure when it occurred or messed on the clothes, does Salaah have to be repeated? If yes, should wudhu also have to be repeated?

Q: My question is about part of the satr becoming exposed during salaah. If someone performs salaah in a t-shirt and his satr becomes exposed whilst going into ruku or sajda, does this have any effect on the salaah?

Q: Is it permissible to read nafl salaah whilst looking inside the Quran and reading?

Q: My father passed away 20 days ago. Alhamdollilah Allah Ta'ala gave me a lot of saber and I did not cry in front of anyone. But every time I pray namaz I just automatically cry. I don't know why this happens. I try so hard to control myself because I am scared that shaitan maybe making me cry. Is it ok to cry in namaaz?

Q: If a person applies Vaseline in his nose and thereafter begins his Salaah. During Salaah he sniffs and the Vaseline goes down his throat. What is the condition of his Salaah?