A 300 mL bottle of soft drink has 0.2M CO$$_2$$ dissolved in it. Assuming CO$$_2$$ behaves as an ideal gas, the volume of the dissolved CO$$_2$$ at STP is ______ mL. (Nearest integer)
Given: At STP, molar volume of an ideal gas is 22.7 L mol$$^{-1}$$

We need to find the volume of dissolved CO$$_2$$ at STP.

The solution has a volume of 300 mL = 0.3 L and a concentration of 0.2 M, so the moles of CO$$_2$$ are 0.3 × 0.2 = 0.06 mol.

At STP, molar volume = 22.7 L/mol, so the volume is 0.06 × 22.7 = 1.362 L = 1362 mL.

The volume of dissolved CO$$_2$$ at STP is $$\boxed{1362}$$ mL.