Q. When   we   say   “Aameen”   at   the   end   of
  supplications  (Dua),  why  can’t  we  say  after
  Surah al-Hamd in congregational prayers?
A. To say “aameen” (May He will it) at the end of
  yours   or   another   person’s   supplication   is
  appropriate. But in a congregational prayer, if it
  is said intentionally as part of the Namaz, the
  Namaz will become void since it is an innovation
  (Bid’at). Imam Mohammad al Baqir (a.s.) said in
  a tradition: “Do not say after qira’at (Ameen).
  You may say if you want Alhamdo Lillah Rabbil
  Aalameen”. Another tradition from Imam Ja’far
  as-Sadiq (a.s.) is that when one mo’min asked
  him: “Shall I say after Al-Hamd (Ameen)?” Imam
  (a.s.) said: “No”. Both these Riwayats and others
  also are mentioned in the famous book Wasail
  al-Shia of al-Hur Al-Aameli. The reason of not
  allowing Ameen in Namaaaz is clear from other
  Riwayat in which Imam Sadiq (a.s.) said: “Indeed
  Christians  used  to  say  (Ameen)”.  It  has  been
  recommended  to  say  “Alhamdo-lillahe-Rabbil-
  Aalameen”. You may say “Aameen” at the end of
  ‘Qunoot’  (praying  with  raised  hands  in  the
  second Rak’at) but not after Surah Al-Hamd.
Q. Some allergy sufferers use an apparatus which
  we call an ‘inhalator’ to assist them in easy
  breathing. After its placement in the mouth and
  pressing it, this apparatus emits what is like
  pressurized gas. Can this apparatus be used at
  the time of fasting?
A. Yes. One who uses this (apparatus) remains on
  his fast and his fast is valid.
Q. Is it permissible to interrupt an obligatory or a

  mustahab tawaf?
A. It is permissible, although it is more in accord
  with caution not to break off during an obligatory
  tawaf  in  a  way  that  is  usually  considered  a
  violation        of     the     continuity        of     sequence
Q. Can a person pool his income from two sources
  before calculating Khums?
A. If you have two different professions, you cannot,
  on the basis of obligatory precaution, make up
  the loss from one side from the profit made from
  the other. But, for example, if you receive rent
  from a property and are also engaged in trade,
  you should pay Khums at the end of the year on
  what exceeds your expenses. And if you make
  profit in one and sustain loss in the other, on the
  basis of recommended precautions, you should
  pay khums on the profit made by you.
Q. Do Shias adopt ‘Taqayya’ (dissimulation) when
  denying ‘Tahreef’ in the Holy Qur’an?
A. No. The Shias believe that there has been no
  ‘Tahreef’ in the Holy Qur’an and the text of the
  Qur’an is pure and has not been tampered with.
Q. How  many  wives  did  Prophet  Mohammed
  (s.a.w.a.) have besides Khadija? What are their
  names, if known?
A. The Holy Prophet (s.a.w.a.) did not marry any
  other woman in the life time of Khadija. After
  her death, he married 12 wives, nine of whom
  were alive at the time of his death. Their names
  were Sauda, Aaisha, Umme Salma, Zainab binte
  Jahash, Safiyya, Hafsa, Maimuna, Zainab Ummul
  Masakin and Umme Habiba.