Degree of dissociation `(alpha)`
`alpha` are the number of moles which are dissociating from 1 mole of given reactants and gas density measurements can be used to determine the degree of dissociatin. Let us take a general case where one molecule of a substance A splits up into n molecules of A(g) on heating i.e.,
`A_(n)(g)hArrnA(g)`
`t=0a`
`t =t_(eq)a-x nx " "alpha=x/aimpliesx=a alpha`
`a-a alpha n a alpha`
Total number of Moles `=a-a alpha +n a alpha`
`=[1+(n-1)alpha]a`
Observed molecular weight of molar mass of the mixture
`M_("mixture")=(M_(A_(n)))/([1+(n-1)alpha]),M_(A_(n))=` Molar mass of `A_(n)`
A sample of mixture A(g), B(g)and C(g) under equlibrium has a mean molecular weight (observed) of 80.
The equlibrium is
`A(g)hArrB(g)+C(g)`
(Mol wt =100)`" "` (Mol. wt=60)`" "` (Mol. wt=40) Calculate the Degree of dissociation for given reaction.

Options

A. `0.25`
B. `0.5`
C. `0.75`
D. `0.8`

Answer

A