How is the zakat calculated for residential land that was purchased with money from the sale of a car whose installments were recently paid off, and when is it due?

If a person buys a residential plot of land with the intention of living on it, there is no zakat due on it. However, if they intend to trade with it, then zakat is due on it if a hawl (a lunar year) passes while it is in their possession. It should be valued at its market price at the time the zakat is due, and a quarter of one-tenth (2.5%) of its value is to be paid.