(1) Tax shall be payable on the sale price of --
         (a) the goods specified in the Schedule II, at the rate of one per cent.;
         (b) the goods specified in the Schedule III, at the rate of four per cent.
        (c) the goods specified in the Schedule IV, at the rate not exceeding fifty per cent. but not less than twenty per cent., as the State Government may, subject to such conditions and restrictions, by notification, specify;
         (d) any other goods, not specified in the Schedules I, II, III and IV, at the rate of twelve and a-half per cent.
     (2) The State Government may, by notification, alter any Schedule to this Act.