Question

While testing oxalate, gas obtained burns with a blue flame initially but is put off instantly even as gas appears coming:

• A. burns due to CO and put off due to $C{O}_2$
  
• B. burns due to C and put off due to $C{O}_2$
  
• C. burns due to $C{O}_2$ and put off due to CO
  
• D. burns due to NO and put off due to $N{O}_2$
• E. None of these

Answer 1

Answer: (A)

burns due to CO and put off due to $C{O}_2$

When the solution of oxalate ion is heated, $CO$ and carbon dioxide gases are evolved. The molecular weight of $CO$ is lower than that of carbon dioxide. Hence, $CO$ diffuses more rapidly than carbon dioxide.
(a) Hence, the $CO$ gas burns.
(b) When heating is continued, carbon dioxide goes upward. It puts off burning $CO$.
$H_2{C}_2{O}_4\stackrel{△}{⟶}{H}_{2}O\left(l\right)+CO\left(g\right)+C{O}_2\left(g\right)$