What volume of oxygen at N.T.P is needed to cause the complete combustion of 200 mL of acetylene ? Also calculate the volume of carbon dioxide formed.

Explanation

The balanced chemical equation is:
`underset(2 xx 22400 cm^(3)) underset(2 mol)(2C_(2)H_(2)) + underset(5 xx 22400 cm^(3))underset(5 "mol")(5O_(2)) to underset(4 xx 22400 cm^(3))underset(4 "mol")(4CO_(2) + 2H_(2)O)`
(i) Calculation of volume of `O_(2)` at S.T.P. required to effect complete combustion of 200 `cm^(3)` of acetylene.
`2 xx 22400 cm^(3)` of acetylene require `O_(2)` for complete combustion `=5 xx 22400 cm^(3)`
`200 cm^(3)` of acetylene require `O_(2)` for complete combustion `=(5 xx 22400)/(2 xx 22400) xx 200`
`=500 cm^(3)` at S.T.P.
(ii) Calculation of volume of carbon dioxide formed
`2 xx 22400 cm^(3)` of acetylene produce `CO_(2)`
`=4 xx 22400`
`therefore 200 cm^(3)` of acetylene produce `CO_(2)`
`=(4 xx 22400)/(2 xx 22400) xx 200`
`=400 cm^(3)` at S.T.P.