(1) No! There is no zakah on that vacant land when it is not bought with the intention of business.
(2) As it is inherited property hence in case it is transferred in your name zakah shall not be liable on the land.
(3) In case it is registered in your name zakah shall not be wajib on you.
(4) Zakah is also not wajib on this land.
Zakah is wajib on land which is bought with the intention of business.
Allah knows Best!
Darul Uloom Deoband