[By Lussac’s law]
2C6H6 + 7O2 → 4CO2 + 6H2O
2 vol : 7 vol → 4 vol : 6 vol
To calculate the volume of unused oxygen.
C6H6 : O2
2 : 7
600 : x
⇒ x = 600 × 7\over 2
⇒ x = 2100 cc
Therefore, volume of unused oxygen = 2500 – 2100 = 400 cc
To calculate the volume of carbon dioxide formed
C6H6 : CO2
2 : 4
600 : x
⇒ x = 600 × 4\over 2 = 1200 cc
Therefore, volume of carbon dioxide formed is 1200 cc