Is zakat obligatory on land that was purchased with the intention of building on it, then selling it to buy another piece of land for residence due to unforeseen circumstances?

There is no zakat on land purchased with the intention of building upon it, nor on its price if another land is purchased with it for building, unless a full year (hawl) passes while it is in the owner's possession. The fact that land is for acquisition (qinya) does not make it a trade asset (ardh al-tijarah) merely by the intention to sell it. Consequently, zakat is not obligatory on its value until after it is sold and a full year passes on its price.