Let, the volume of oxygen in 1120 mL of ozonized oxygen be x mL at S.T.P.
Volume of ozone =(1120−x) mL at S.T.P.
We known that, mass = vol. of mixture × density
mass = vol. of oxygen × it’s density + vol. of ozone × it’s density
Density of O2 at STP =3222400 g/mL
Density of O3 at STP =4822400 g/mL
1.76=x×3222400+(1120−x)×4822400
⇒1.76×22400=32x+53760−48x
⇒16x=(53760−39424) mL
⇒x=896 mL