A 3:
First: It is impermissible for a Muslim woman to marry a non-Muslim. In this regard, Allah (Exalted be He) stated:
And give not (your daughters) in marriage to Al-Mushrikûn till they believe (in Allâh Alone)
He (Glorified be He) also stated:
...then if you ascertain that they are true believers, send them not back to the disbelievers. They are not lawful (wives) for the disbelievers nor are the disbelievers lawful (husbands) for them.
Moreover,
a woman who embraces Islam while married to a non-Muslim has to immediately separate from him.
Second:
A Muslim woman who dies while married to a non-Muslim must be washed and shrouded, Janazah Prayer must be offered for her, and she must be buried in a Muslim cemetery. (Part No. 7; Page No. 282) May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.