Those things which render the Salaah invalid

Q: If someone is offering namaz and during namaz he feels that his wudhu is broken then what should he do in such a situation? Specifically if he is in the last rakaat?

Q: Please advise with regard to the following:

Is it permissible for a Musallee to look inside the Quraan during Taraweeh? If not, is there any social occasion in which it would be permissible?

If we are 3 people in our Taraaweeh Jamaat - the Imaam and one Musallee is a Hafiz, but their dhor is not so good and plan to improve it by performing Taraaweeh - will it be permissible for the Musallee to look into the Quraan during the Salah?

Q: I am following Hanafi Fiqh.

1. In the current situation of Palestine, I have started reading Qunut e Nazila in Fajr prayer. I restrict myself with the Arabic dua from Quran and Hadith. However, I said one day, allahummansuril mujahideena fi filasteen (in Arabic). Would that be considered as Kalamun nas?

2. Secondly, could you please let me know about the guideline which will be easy for me to understand the Kalamun Nas discussed by the fuqaha. I have heard that if we are making dua in Arabic outside Quran and Hadith, it should not be in the classification of Kalamun Nas. However, this thing did not become clear so that's why I am refering to you.

Q: The imaam in the Fajr Salaah recited Qunoote Naazilah. During the Qunoot, he read the following in error: ولا يضل من عاديت

Will the salaah be valid in such a situation or will it break?

Q: The problem I face throughout the prayer is that I feel laughter in my chest. I think it comes from fear of breaking prayer due to laughter. There are times when I compulsively (quite intentionally) pronounce letters, especially "haa", mixed with laughter and sometimes, by forgetfulness.

Most of the time, voice cracks continously while reciting and very little part of my voice is audible (due to uncleared throat) and feelings of laughter seem to get mixed. Can you please let me know what is the type of laughter that breaks Namaz? I keep feeling every Namaz is invalid.

Q: My routine in Tahajjud Salaah is to recite daily one juzz from the Quran in a bit of a loud voice from my mobile or I-pad fixed on a stand before me. Please inform me whether this is acceptable as per Islamic rules.

Q: If you think about something funny in salaah, and you don't fully laugh but a small sound is made from the mouth, then are the salaah and the wudhu broken?

Q: How thick may a musallah (prayer mat) be? I bought a thick musallah (prayer mat) and I want to know that when performing sajdah on it, should the head and nose feel the earth or carpet below it (prayer rug) in order for the sajdah to be valid?

Q: Is the prayer of someone who has inserted something into its rectum (to block flatulence) before doing wudhu and removed it after praying valid?

Q:

1. If I use my hand, due to losing balance, when coming up from sajdah, will this break my salaah?

2. Whilst making my niyyah for salaah, at the beginning I scratched my face and then used my one hand twice in salaah. Is this amal-e-katheer?