Question

An organic compound is estimated through Dumas method and was found to evolved 6 moles of CO₂. 4 moles of H₂O and 1 mole of nitrogen gas. The formula of the compound is
1. C₆H₈N
2. C₁₂H₈N
3. C₁₂H₈N₂
4. C₆H₈N₂

Answer 1

Correct Answer - Option 4 : C₆H₈N₂

Concept:

In Dumas method, organic compound is heated with dry cupric oxide in a combustion tube in the atmosphere of CO₂. Upon heating, C and H present are oxidised to CO₂ and water vapours while N₂ is set free. Let, the molecular formula of the organic compound (1mol) be C_xH_yN_z. In Dumas method,

\({C_x}{H_y}{N_z} + \left( {2x + \frac{y}{2}} \right)CuO \to xC{O_2} + \frac{y}{2}{H_2}O + \frac{z}{2}{N_2} + \left( {2x + \frac{y}{2}} \right)Cu\)

x mol \(\frac{y}{2}mol{\rm{\;}}\frac{z}{2}mol\)

Now, x = 6, \(\frac{y}{2} = 4 \Rightarrow y = 8{\rm{\;and\;}}\frac{z}{2} = 2 \Rightarrow z = 2\)

∴ Molecular formula of the compound is C₆H₈N₂