Mg reacts with 150 mL of 6.00M Hcl through single replacement to produce hydrogen gas. How many liters of hydrogen gas are produced? (tell me how you got it please)

Answer 1

I assume this is for STP.
Write and balance the equation.
Mg + 2HCl ==> H2 + MgCl2

How many moles HCl did you use? M x L = moles.
Using the coefficients in the balanced equation, convert moles HCl to moles H2.
Now convert moles H2 to liters knowing that 1 mole H2 gas occupies 22.4 L at STP.
Post your work if you get stuck.