(1) If the Administrator is of opinion that it is necessary or expedient in the public interest so to do, he may, with the previous approval of the Central Government, exempt, by notification in the Official Gazette, and subject to such conditions, if any, as he may impose, any specified class of sales by any specified class of dealers from payment of the whole or any part of the tax payable under this Act.
     (2) If in respect of any sales which are exempt from payment of tax under sub-section (1), a breach of any of the conditions subject to which such exemption was granted, is committed, the dealer responsible for such breach shall be liable to pay tax in respect of all such sales as if no such exemption had been granted.