You cannot apply this year's tax refund to a prior year taxes owed on a federal tax return.
The IRS knows you have back taxes owed and will seize your tax refund and apply the refund to the taxes owed. Any remainder and the IRS will send you the rest of the refund. If the refund does not satisfy the debt the IRS will send you a bill in the mail for the taxes owed plus penalties and interest.
