Ramadhaan & Fasting

Fasting so that one's dua will be answered

Q: The Prophet (Sallallahu Alayhi Wasallam) said that the dua of a fasting person is answered. It's borne on the clouds and the gates of heaven are opened for it, and Allah (Ta'ala) says "By my glory, I will grant you help even if it may be after sometime". Can I fast with the intention that my dua will be answered, or is that disliked? Any help will be greatly appreciated.

Sadaqatul fitr

Q: Please clarify the following:

1. Is fitrah obligatory on every individual or is it the duty of the head of the household to pay it on Eid-ul-Adha?

2. If the fitrah wasn't paid on time then what is due on the person?

3. How much is fitrah?

Woman's I'itikaaf breaking due to haidh

Q: I made an intention for sunnah itekaaf in Ramadaan. Unfortunately I was only able to sit seven days due to haiz. (Mufti I had miscalculated my days.) I have sat 1 day in itekaaf as qazaa and my intention for the fast was for a Ramadaan qazaa fast. Is this correct or do I sit for 3 days in itekaaf? Is my fast correct? Mufti was I sinful in miscalculating my days? It grieves me greatly. Please advise.