Qiraat in Salaah

Q: Does recitation of الله رب العالمين (After Surah Mulk) break ones Salaah?

Q: 

1. During Salah, while I am reciting a surah or something else, must I stop reciting to breathe in or out through my mouth and then continue or can I keep on reciting while I take a breath? 

2. The same question as above for yawning.

Q: After reciting Surah Ikhlaas in salaah, I mistakenly said sadaqallahul azeem. Is my salaah valid or is there sajdah sahw?

Q: When you want to read a big surah in salaah, but not in full. Is it okay to read from anywhere in the surah and stop anywhere? And can you read one part of a surah in the first rakaat, the part after that in the second rakaat? Or do you have to read different surahs in each rakaat? 

Q: As we know it is waajib to recite the first 3 verses of Surah Faatiha in every rakaah of salaah.

I heard a mufti say that qiraat changes the amount of verses in the Quraan. If I recite the first three verses of Surah Faatiha and combine the second and third verse and not recite further would my prayer be valid?

Q: What's the sunnah method of reading Surah Faatiha in salaah? Each ayah a different breath? Or joining more than one ayah in one breath?

Q: How many verses of Surah Fatiha is waajib to recite in salaah?

Q: During my witr salaah, sunnah muakkadah salaah and nafl salaah, how loud can I read qiraat? Can it be as loud to the extent that people close to me can hear me?

Q: Is there any qawl amongst the ulama which stats that the sunnat qiraat in salaah is not which surahs are recited but rather the amount recited?