In Dumas method one gram of carbon compound gives (50 ~mL ) of ( N ₂ ) at (300 ~K ) and (740 ~mm Hg ) pressure. If the aqueous tension at (300 ~K ) is (15 ~mm Hg ), what is the percentage of nitrogen in it?

Step-by-step solution

Given, (p=740 ~mm ) of ( Hg ) dry gas pressure (p₁=740-15=725 ~mm Hg ) (V₁=50 ~mL ) (T₁=300 ~K , p₂=760 ~mm Hg , T₂=273 ~K ) From the combine gas equation, ( gathered p₁ V₁ T₁ = p₂ V₂ T₂ 725 50 300 = 760 V₂ 273 gathered ) (V₂= 725 50 273 300 760 =43.4 ~mL ) (22.4 ~L ) of ( N ₂ 28 ~g ) of ( N ₂ ) at STP (22400 mL) (43.4 ~L _ of N ₂ 28 434 22400 =5.4 10⁻² ~g ) of ( N ₂ ) ( % ) mass of ( N ₂= Mass of N ₂ Mass of substance 100 ) (= 5.4 10⁻² 1 100=5.4 % ) Hence, option (1) is correct.