When a mixture of 12.0 g of acetylene (c2h2 and 12.0 g of oxygen (o2 is ignited, the resultant combustion reaction produces co2 and h2o?

The product of the complete combustion of any fuel (in this case, acetylene) are indeed water and carbon dioxide.

Balancing the combustion reaction,

C2H2 + (5/2) O2 - - > 2CO2 + H2O

The number of moles of C2H2 will be,

(12 g) x (1 mole/26 g) = 6/13 mole

Then, the number of moles of O2 is,

(12 g) x (1 mole/32 g) = 3/8 mole

Therefore the limiting reaction is the O2. Getting the amount of CO2 and H2O produced from balancing,

CO2 = (3/8 moles) x (2 moles CO2 / 5/2 mole O2) (44 g / 1 mole) = 52.8 g

H2O = (3/8 moles) x (1 mole / 5/2 mole O2) (18 g / 1 mole) = 2.7 g