(a) All pecuniary legacies given in any will shall, if the personal property of the testator is insufficient for the payment thereof, be a charge on his real property not specifically described and devised, unless otherwise directed in such will.
(b) Specific legacies shall not be taken or sold for the payment of debts and charges against the estate of the testator when there is other property, real or personal, sufficient and available therefor and not specifically devised or bequeathed; but real property may be sold in lieu thereof, when it is necessary for such purpose, unless such will otherwise directs.