A pious man proposed to me and my father was hesitant in this regard because he is black, am I sinful if I accepted his proposal?
If the suitor is pious, color isn`t a drawback. However, try talking to your father kindly, so that he approves of your marriage with contentment, and that is better for you.
Is it permissible for a woman to offer the obligatory prayer after Adhaan (call for prayer), and before Iqamah (The announcement that the prayer is about to begin) in the mosque?
Yes, it is permissible for a woman to offer the obligatory prayer immediately after the Adhan and before the Iqamah in the mosque. And Allah 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.
Can Zakah or Zakat al-Fitr be given to a poor brother?
Yes, it is allowed to give Zakah or Zakat al-Fitr to a poor brother, as he is considered among the eligible recipients.