Consider the reaction : C2H4 + 2Co2+ 2H20.calculate the volume of Co2 produced at s.t. p when 0.05 mole of C2H4 was burnt in Co2

You should proof your posts. You didn't add the O2 into the equation and you don't show an arrow.

C2H4 + 2Co2+ 2H20 corrected below.
C2H4 + 3O2 ==> 2CO2+ 2H2O
0.05 mols C2H4 will produce 2*0.05 = 0.1 mol CO2.
Remember that @ STP 1 mol CO2 will occupy 22.4 L.
Post your work if you get stuck.