Can someone who begins a voluntary fast break it?
It is preferable for someone who begins an act of worship not to break it.
Allah the Exalted has said {what means}: "and let not your [good] deeds come to nought!" [Muhammad/33].
However, if a person starts a voluntary fast (nafl) and needs to break it, they are going against what is preferable, but there is no sin upon them.
What is the ruling on swearing on the Holy Quran and breaking that oath?
It is impermissible to swear on the Holy Quran in vain, and it is also impermissible to subject it to such an act since breaking the oath after swearing on the Quran entails an expiation.
What is the ruling of Islamic Law on participating in the prize draws (raffles) that commercial stores hold for their customers?
Praise be to Allah, and peace and blessings upon our master, the Messenger of Allah.
There is no objection to participating in the prize draws (raffles) that commercial stores hold for their customers, provided that the buyer's intention in purchasing is not merely to enter the competition without any need for what is bought — rather, the purchase must be genuinely intended for the item itself, and one must not pay more than the item's fair market price. This is because paying an amount above the market price would effectively be paying a fee to enter the prize draw, which would render it a form of gambling (qimār).
These prizes are, in essence, gifts that businesses offer through a random drawing (qur'ah) to those who purchase from them, as a means of encouraging sales, without the customer bearing any additional monetary cost for participation. So long as the aforementioned conditions are met, there is no objection to benefiting from the prize offered by the store, as it is considered a lawful prize from the viewpoint of Islamic Law.
It is stated in the resolutions of the "Jordanian Iftaa' Board" (Resolution No. 47), in the context of outlining the conditions for permissible prizes: "The price of the ticket [or item purchased] for the sake of the prize must not exceed its original price, so that there is no payment of money in exchange for participation in the draw." And Allah, the Most High, knows best.
What is the ruling of Islamic Law on supplicating with other than the transmitted (Ma'thur) supplications in prayer?
All praise is due to Allah, and peace and blessings be upon our master, the Messenger of Allah.
It is permissible to supplicate (make du'a) during the prayer for anything from the affairs of religion or worldly life, and the prayer is not invalidated by doing so.
Shaykh al-Islam, the Imam an-Nawawi, may Allah have mercy on him, says: "Our madhhab [i.e., the Shafi'i madhhab] holds that it is permissible for a person to supplicate during it [the prayer] with anything that is permissible to supplicate with outside the prayer, from the affairs of religion or worldly life. He may say: 'O Allah, grant me wholesome sustenance, offspring, a house, and a beautiful young wife' — describing her; or: 'O Allah, free so-and-so from prison,' or 'destroy so-and-so,' and other such things — and none of this invalidates his prayer according to us. And this is also the view of Malik, ath-Thawri, Abu Thawr, and Ishaq." [Al-Majmu', Vol.3/P.454]. And Allah, the Exalted, knows best.