What is the ruling on wiping the head during ablution from behind a barrier like a headscarf (hijab)?
The obligation in ablution is to wipe some of the head; it is not a condition to wipe all of it. As for one who has a turban or headscarf on their head, it is permissible for them to wipe over it after wiping a part of their head in any place. This is easily done at the front of the head. This means the woman begins by wiping the front of her head from under the headscarf, then completes the wiping to the back of the head from over the headscarf. If the woman wipes over the headscarf on her head and the moisture reaches the scalp or some hair within the boundaries of the head, it suffices for wiping the head. And Allah the Almighty knows best.
What is the ruling on one who doubts washing a limb before or after finishing ablution?
If a person performing ablution doubts leaving the washing of a limb from the limbs of ablution during his ablution, he must repeat washing that limb and wash what comes after it. If he doubts leaving the washing of a limb after finishing the ablution, there is nothing upon him. And Allah the Almighty knows best.
What is the ruling on a woman who learns of her divorce or her husband's death after her *ʿiddah* has ended? And does the *ʿiddah* of a woman who abandoned mourning (*iḥdād*) for the whole period of the *ʿiddah*, or part of it, still end, even though she knew that abandoning it is forbidden?**
All praise is due to Allah, and peace and blessings be upon our master, the Messenger of Allah.
The waiting period of a widow who is not pregnant is four months and ten days, based on the saying of Allah Almighty (which means): “And those of you who die and leave wives behind, they shall wait concerning themselves for four months and ten days” [al-Baqarah/234]. If she is pregnant, her ʿiddah ends with the delivery of her child. The ʿiddah is calculated by lunar months and begins from the date of death.
If her ʿiddah ends before she learns of her husband’s death, or of his divorcing her, she does not observe the ʿiddah upon learning of it, because her ʿiddah has already ended.
It is stated in al-Bayān fī Madhhab al-Imām al-Shāfiʿī (Vol.11/p.41), one of the books of the Shāfiʿī school: “If a man divorces his wife, or dies while he is absent from her, her ʿiddah is from the time of the divorce or from the time of death. If she does not know of the divorce or the death until her ʿiddah period has ended, then her ʿiddah has ended. If she learns of it before the end of the ʿiddah period, she completes her ʿiddah counting from the time of the divorce or death.”
As for a woman who abandoned mourning throughout the ʿiddah while knowing that it is forbidden, she is sinful, although her ʿiddah has nonetheless ended. And Allah Almighty knows best.
Is it permissible for a woman to wear underwear while performing Umrah?
Yes, it is permissible for a woman to wear underwear while performing Umrah. This is because she should keep her regular clothes that cover all her body while being in a state of Ihram (ritual consecration) for Hajj, or Umrah. However, she should uncover her face and hands, but it is permissible for her to let her head-covering garment drape from her head down over her face when non-Mahram (i.e., marriageable) men pass by her. And Allah Knows Best.