Is it permissible to mortgage an agreed-upon land sale, and is it permissible to take possession of the mortgage if the term expires?

A mortgage is a document for debt, and it is permissible to take it for all necessary debts. The mortgagee has no right to the mortgaged item except to the extent of his debt. If the debt becomes due, the mortgagor is asked to sell it to fulfill the right. Otherwise, the matter is brought before a judge to compel him to sell it or to undertake the sale himself.