How should I deal with the whispers of the devil with regard to ablution and purity?
Whispers in ablution are from the devil, and so you should take refuge in Allah from the devil`s evil suggestions that aim to distort the religion. Thus, once an organ is completely pure, don`t question its purity since having whispers doesn`t mean that the purity is invalid as it has already been established.
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 a woman using contraception without her husband's knowledge if he is mistreating her?
All praise is due to Allah, and peace and blessings be upon our master the Messenger of Allah ﷺ.
It is not permissible for a woman to use any means of delaying pregnancy without her husband's knowledge, consent, and mutual agreement. This is because having children is a sharʿī right belonging to both spouses equally in Islamic law. Imām al-Māwardī, may Allah have mercy upon him, stated: "The right to a child from a free woman is shared between them both" — meaning between the two spouses. [al-Ḥāwī al-Kabīr, 9/320]
It is therefore not permissible for either spouse to make a unilateral decision regarding the prevention of pregnancy without the consent of the other. We advise both spouses to discuss the matter with wisdom and mutual respect, so as to resolve any disagreement and arrive at a suitable solution that serves the interests of them both. And Allah the Almighty knows best.
Where should a woman following her husband or another man in prayer stand?
Praise be to Allah, and peace and blessings be upon our Master, the Messenger of Allah.
If a single woman prays with a man—whether she is his wife or a non-mahram (Ajnabiyyah)—the Sunnah is for her to stand behind the Imam and be shielded by him. If the Imam is leading both a man and a woman, the man should stand to the Imam's right, and the woman should stand behind the male follower (Muqtadi). In this way, she is shielded from the Imam by the male follower and remains at a distance from the follower and his line of sight. And Allah the Exalted knows best.