What is the correct point at which to raise the hands when standing up for the third rak‘ah (after the middle tashahhud)?
All praise is due to Allah, and peace and blessings be upon our master, the Messenger of Allah ﷺ.
Raising the hands while saying the takbīr [when rising for the third rak‘ah] is a recommended sunnah, and omitting it does not affect the validity of the prayer. The proper time for this is after rising from the middle tashahhud, once one has fully stood up.
It is stated in I‘ānat aṭ-Ṭālibīn (Vol.1/P.158): "His statement, 'and rising from the first tashahhud' — meaning, this manner [of raising the hands] is also a sunnah when he rises from the first tashahhud, that is, when he stands upright from it.
Consider [the question]: when precisely does the raising of the hands begin? Is it at the very start of rising from the first tashahhud, or after he has reached the minimum position of rukū‘ [i.e., once fully upright]? The apparent, [correct] view is the latter — even though the outward wording [of the text] might suggest the former — because at the very start of his rising, he is still relying on both hands [to push himself up, and therefore cannot yet raise them]."
It is stated in ‘Umdat as-Sālik (p. 53): "If his prayer extends beyond two rak‘ahs, he sits after them in the iftirāsh position, recites the tashahhud, and sends blessings upon the Prophet ﷺ alone, without [mentioning] his family [at this point]. He then stands while saying the takbīr, supporting himself with his hands; and once he has stood upright, he raises them level with his shoulders." And Allah, the Exalted, knows best.
Is it valid to perform Tarawih prayer at home?
It is Sunnah for a Muslim to perform Tarawih prayer in congregation at the mosque.
However, if a person sometimes prays it at home in congregation with their family for a valid reason, there is no harm in doing so.
Is it obligatory to have the intention for each day of fasting, or is one intention sufficient for the whole month?
The intention is obligatory for each day of Ramadan because each day is an independent act of worship separate from the others.
The intention must be made at night before the break of dawn, as the Prophetﷺ said: "Whoever does not intend fasting at night, there is no fast for him." [An-Nasa’i]
And he also said: "Whoever does not firmly resolve to fast before dawn, there is no fast for him." [At-Tirmidhi, Abu Dawood, and An-Nasa’i]
Whoever wakes up and eats Suhoor while mindful of fasting has made the intention. Likewise, one who firmly intends at any moment during the night to fast the next day has also fulfilled the intention.
Is it permissible for a praying person to make supplication in each Sajdah (a prostration) of obligatory prayer?
It is permissible for a praying person, whether praying individually, or in congregation, to make supplication during Sujood (prostration) in obligatory, or voluntary prayers. However, it is disliked for the Imam to do so since he is required to spare the prayer performers any sort of hardship, unless he is leading a certain group who don`t mind him extending the prayer.