Is the wife obligated to pay zakat on the husband's bank deposit from her own money, and is it permissible for her and her children to benefit from the profits of this deposit?

Zakat on wealth is obligatory for its owner. If the wealth belongs to the husband, he is responsible for paying Zakat, even if it is registered in the wife's name, unless he has gifted it to her. It is not permissible for the wife to pay Zakat on the husband's behalf from his wealth unless he gives her permission; otherwise, the Zakat will not be valid due to the lack of intention.

If the deposit is in an interest-based bank (riba bank), then depositing and earning interest are forbidden (haram). Repentance is obligatory, the amount must be withdrawn, and the usurious interest must be disposed of by spending it on the welfare of Muslims or giving it to the poor and needy. The forbidden interest is not subject to Zakat; rather, only lawful wealth is subject to Zakat.

However, if the wealth is invested in an Islamic bank, then the profit (interest) is subject to Zakat along with the principal amount.

The wife is not permitted to dispose of her husband's wealth without his permission, nor should she take anything from it without his permission, unless he fails to spend on her or their children; in such a case, she is permitted to take what suffices her in a reasonable manner.