Is zakat obligatory on a sum of money for the purchase of a home that is still in the buyer's possession and has not been handed over to the seller until the home is vacated?

If a man buys a house and retains the price, not handing it over to the seller until the seller vacates the house, this condition is permissible. The buyer must pay zakat on this amount because it is still in his possession, and his ownership of it is established. He can dispose of it as he wishes. The seller's right is not in the specific money itself, but rather it is related to the buyer's financial obligation. A condition for the obligation of zakat is the established ownership of the nisab, and here the buyer's ownership of the money is established, so zakat is due upon him.