$H_2C_2O_4 \xrightarrow{\Delta } \text{gas } (A) + \text{gas } (B) + \text{liquid } (C)$.
$\text{Gas } (A) \text{ burns with a blue flame and is oxidised to gas } (B)$.
$\text{Gas } (A) + Cl_2 \to (D) \xrightarrow{NH_3, \Delta } (E)$.
$A, B, C \text{ and } E \text{ are}$

• A
  $CO_2, CO, H_2O, HCONH_2$
• B
  $CO, CO_2, COCl_2, HCONH_2$
• C
  $CO, CO_2, H_2O, NH_2CONH_2$
• D
  $CO, CO_2, H_2O, COCl_2$