Let the weight of CO in the mixture be x g.
Total weight of mixture =1.28g
Weight of CO2=1.28−x
Moleculr weight of CO=28g
Molecular weight of CO2=44g
Moles of CO2 in the mixture =1.28−x44
Moles of CO in the mixture =x28
At NTP, the volume occupied by 1 mole of a gas =22400mL
∴ 896 mL occupied by 122400×896=0.04 moles
∴ Total moles in the mixture = 0.04 moles
⇒ Moles of CO2+ Moles of CO=0.04
⇒1.28−x44+x28=0.04
⇒35.84−28x+44x=49.28
⇒16x=13.44
⇒x=0.84
∴ Molecular weight of CO2=1.28−0.84=0.44g
∴ Moles of CO2 in the mixture =0.4444=0.01 moles
∵ Volume occupied by 1 mole of CO2=22400mL
⇒ Volume occupied by 0.01 mole of CO2=22400×0.01=224mL
Hence, at NTP, 224 mL of CO2 is present in the mixture.