Is Zakat obligatory on real estate that was purchased with the intention of dwelling, then its intention changed to trading, knowing that some of it has been sold and the proceeds from the remainder were used to purchase another property with the intention of trading?

Zakat is not obligatory on your share of the land and building if you intend it for personal use (qinya). Rather, Zakat becomes obligatory on its price after the completion of a full year (hawl), according to the majority of scholars. Debts are deducted from the price, and the remaining amount is subject to Zakat, if it reaches the nisab, at a rate of a quarter of a tenth (2.5%). A group of scholars, however, held the view that as soon as the intention for trade is formed, it becomes a trade commodity (urud al-tijara) and Zakat becomes obligatory on it. The Zakat year begins from the time the intention to trade is made, and its Zakat (a quarter of a tenth) is to be paid from its value or price upon the completion of the hawl.