Is Zakat obligatory on a rented house, the rent of which is spent on the family's living expenses; and on an amount deposited in an Islamic bank – and does the bank undertake the disbursement of Zakat; and is Zakat obligatory on ornamental gold; and is it permissible to distribute Zakat to relatives of middle or lower income?

Zakat is due on wages if they reach the nisab and a full year has passed over them. It is not due on them if they are spent before the end of the year. As for a deposit, its zakat is due at the end of each Hijri year if it reaches the nisab. The principle is that the bank does not disburse zakat. If you trust that they will disburse it to its rightful beneficiaries, then it is permissible to appoint them as an agent. Otherwise, you must disburse it yourselves. Allah Almighty has clarified the beneficiaries of zakat in the verse: "Indeed, [prescribed] charitable offerings are only for the poor and the needy, and those who work on [collecting] them, and those whose hearts are to be reconciled, and for [freeing] captives, and for those in debt, and for the cause of Allah, and for the wayfarer; [this is] an obligation from Allah. And Allah is Knowing and Wise." Relatives have a greater right to zakat if they belong to these categories and do not find enough to cover their basic needs. The obligatory amount of zakat is one-fourth of one-tenth (2.5%).