1.78 g of an optically active L-amino acid (A) is treated with `NaNO_2//HCl` at `0^(@)` C. `448 cm^(3)` of nitrogen was at STP is evolved. A sample of protein has 0.25% of this amino acid by mass. The molar mass of the protein is

Options

A. `36, 500 "g mol"^(-1)`
B. `34, 500 "g mol"^(-1)`
C. `35, 400 "g mol"^(-1)`
D. `35, 600 "g mol"^(-1)`

Answer

D

Explanation

`underset((A)" ")("L-amino acid" underset(0^(@)C)overset(NaNO_(2)+HCl)rarr N_(2)uarr)`
1 mole of L-amino acid `rarr` 1 mole of `N_(2)=22400cm^(3) ` of `N_(2)` at STP
`448cm^(3)` of `N_(2)-=1.78g` of L-amino acid
`22,400 cm^(3)` of `N_(2)-=x` g of L-amino acid
`x=(1.78xx22,400)/(448)=89g` of L-amino acid.
`{:("Amino acid","Protein"),(" "0.25," "100),(" "89," "y):}`
`y=(89xx100)/(0.25)=35,600`g/mol