This is a limiting reactant problem.
We know that we will need a balanced equation and moles of each reactant.
1. Gather all the information in one place with the experimental number of moles below the formulas.
$color(white)(mmmmmm)2x + 3y + 4z = 5w$
$"Amt/mol:"color(white)(ml)1color(white)(mm)3"color(white)(mm)4$
$"Divide by:"color(white)(ml)2color(white)(mm)3color(white)(mm)4$
$"Moles rxn:"color(white)(m)0.5color(white)(ml)1color(white)(mm)1$
2. Identify the limiting reactant
An easy way to identify the limiting reactant is to calculate the "moles of reaction" each will give:
You divide the moles of each reactant by its corresponding coefficient in the balanced equation.
I did that for you in the table above.
$x$ is the limiting reactant because it gives the fewest moles of reaction.
3. Calculate the theoretical yield of $w$
$"Theoretical yield" = 1 color(red)(cancel(color(black)("mol"color(white)(l) x))) × ("5 mol " w)/(2 color(red)(cancel(color(black)("mol "x)))) = "2.5 mol"color(white)(l)w$
4. Calculate the percent yield
$"Percent yield" = "Actual yield"/"Theoretical yield" × 100 % = (1.25 color(red)(cancel(color(black)("mol"))))/(2.5 color(red)(cancel(color(black)("mol")))) × 100 % = 50 %$