Question

An alkane on complete combusion with O2 shows 50% of volume contraction. Molecular formula of alkane is-

Answer 1

General equation for combustion :CxHy + (x+y/4)O2 → xCO2 + y/2H2O​According to question :(x+(y/4))/x = 7/4Solving the equation we obtain:4x + y = 7x ory=3xy/x = 3/1Thus the alkane is of the type:CxH3xGaseous alkanes are CH4 , C2H6 , C3H8 ,C4H10 only and only gaseous alkane with formula of this type is C2H6.

Answer 2

The formula for alkaline is 2 / 3n + 1 x no2. When you put across, you need to find n in this equation. It comes to 5 = 2 / 3n + 1 x 25.

n will be equal to 3. And then the milecular formula for alkane comes to C3H8