Is my husband entitled to take my salary?
Your salary is yours, and you may give some of it to him as a kind of free-will contribution.
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 of Islam on swearing by Allah without intending to take an actual oath?
Praise be to Allah, and peace and blessings be upon our Master, the Messenger of Allah.
If someone swears by Allah without intending to take an actual oath, and without the firm resolve to bind themselves to it, then there is no sin or expiation (Kaffarah) required of them. Allah the Exalted says {what means}: 'God will not call you to account for thoughtlessness in your oaths, but for the intention in your hearts; and He is Oft-forgiving, Most Forbearing.' [Al-Baqarah/225]. However, a Muslim should avoid swearing oaths excessively so that their tongue does not become accustomed to it. Allah the Exalted says {what means}: 'And make not God’s (name) an excuse in your oaths against doing good, or acting rightly, or making peace between persons; for God is One Who heareth and knoweth all things.
' [Al-Baqarah/224]. And Allah the Exalted knows best."
Is it permissible for a woman to ride a taxi without a Mahram (unmarriageable kin) in order to attend a gathering of knowledge?
It is permissible for the woman to pursue the knowledge that she needs in order to perform the religious requirements due on her if there was nobody to teach her at home, provided that there is no temptation involved. Moreover, we don`t recommend that she rides a taxi without a Mahram although such an act isn`t from the forbidden Khulwah (seclusion).