120ml of ozonised oxygen containing 90% oxygen is heated and cooled to original conditions. If all the ozone in the sample is converted to oxygen then the volume of oxygen finally will be

Percentage of oxygen in ozonised oxygen = 90%                Total volume of ozonised oxygen =120cc                Volume of oxygen = 120 ×90 /100 = 108cc                Volume of ozone = 120 -108 =12cc            Upon heating ozone is converted into oxygen           2O3(g)→heat3O2(g)           Volume of oxygen formed from 12cc of ozone = 18cc         Total volume of oxygen at the end = 108 + 18 =126cc