CHEMISTRY (pls show ur steps in detail )?

Let CₘHₙ be the molecular formula of the hydrocarbon.

The equation for the combustion reaction:
CₘHₙ(g) + [m + (n/4)]O₂(g) → mCO₂(g) + (n/2)H₂O(g)

volume ratio CₘHₙ : O₂ : CO₂ is
1 : [m + (n/4)] : m = (100 mL) : (450 mL) : (300 mL)
1 : [m + (n/4)] : m = 1 : 4.5 : 3
m + (n/4) = 4.5 and m = 3
Hence, m = 3 and n = 6

Molecular formula = C₃H₆

Write an equation ( divide volumes by 100 for convenience)
1CH + 4.5O2 → 3CO2 + xH2O
2CH + 9O2 → 6CO2 + xH2O
You have 6C in products. 2C in reactants.
Adjust CH to give 6C
2C3H +9O2 → 6CO2 + xH2O
Now sort out H using O
You have 18 O atoms in reactants but 12 O from 6 CO2. Therefore there must be 6 O associated with the H2O
Equation
2C3H + 9O2 → 6CO2 + 6H2O
Adjust 2C3H to balance H
2C3H6 + 9O2 → 6CO2 + 6H2O

Hydrocarbon: C3H6 cyclopropane