The equation of the chemical reaction between magnesium and hydrochloric acid is: Mg(s) + 2HCl (aq) ---> MgCl2 (aq) + H2

From the equation it is seen that 2 moles of hydrochloric acid are needed to react with one mole of magnesium.

The molar mass of magnesium is 24.30 g/mole. 6.08 g of magnesium is equivalent to 6.08/24.30 or approximately 0.25 moles. 0.25*2 = 0.5 mole of hydrochloric acid is required to react with the magnesium. As the concentration of hydrochloric acid is 0.04 M or 0.04 mole/liter, the volume of acid required is 2*0.25/0.04 = 12.5 liters.

The volume of 0.04 M hydrochloric acid required for the given reaction with 6.08 g of magnesium is 12.5 liters.