Aslam

Praise be to Allah.In Fataawa al-Lajnah al-Daa’imah

wa’l-Buhooth (6/392) it says the following:

It was reported that the Prophet

(peace and blessings of Allaah be

upon him) used to recite aloud in the two Rak’ahs of Subh (Fajr), and in the first

two rak’ahs of Maghrib and ‘Ishaa’. So reciting aloud in these cases is

Sunnah, and it is prescribed for his Ummah to follow his example, because Allaah says

(interpretation of the meaning):

“Indeed in the Messenger of Allaah you have a good example to

follow for him who hopes in (the Meeting with) Allaah and the Last Day and remembers

Allaah much.” [al-Ahzaab 33:21].

It was reported that the Prophet

(peace and blessings of Allaah be

upon him) said: “Pray as you have seen me praying.”

Reciting silently when one is supposed to recite aloud implies that one

is neglecting the Sunnah, even though this does not invalidate the prayer.

So the Muslim should recite aloud during Fajr prayer and in the first

two rak’ahs of Maghrib and ‘Ishaa’, even if he is praying alone, because

this is the Sunnah.

He should not recite aloud during Zuhr and ‘Asr. He should recite

aloud during the first two rak’ahs of Maghrib and ‘Ishaa’, and in the fard

of Fajr prayer, and he should recite silently in the third Rak’ah of Maghrib and in

the last two rak’ahs of ‘Ishaa’. These times of reciting aloud or silently

are mustahabb when praying alone, according to Imaam al-Shaafa’i and others. The

Hanbalis say: the person who is praying alone has the choice of reciting aloud at the

appropriate points; if he wants to he may recite aloud, and if he wants to he may lower

his voice.

(al-Mufassal li Ahkaam al-Mar’ah by ‘Abd al-Kareem

Zaydaan, p. 330).

With regard to the second part of your question, in Fataawa

al-Lajnah al-Daa’imah wa’l-Buhooth (6/56) its says:

It is permissible for a person praying alone to pray without the

Adhaan, but if he is in the desert or on a remote farm and the like, it is prescribed for

him to recite the Adhaan even if he is going to pray alone, and the Iqaamah is prescribed

at all times, because of the general meaning of the evidence, and because Abu Sa’eed

al-Khudri said to ‘Abd-Allaah al-Ansaari: “I see that you like sheep and the

wilderness. When you are with your sheep in your wilderness, and you recite the Adhaan for

your prayers, raise your voice, for no jinn or man or anything within the voice range of

the muezzin hears the call, but will bear witness for him on the Day of

Resurrection.” Abu Sa’eed said: I heard this from the Messenger of Allaah

(peace and blessings of Allaah be upon him).

(Narrated by al-Bukhaari, 1/151).

And Allaah is the Source of strength. May Allaah bless

our Prophet Muhammad and his family and companions, and grant them peace.