question_answer

\[{{C}_{4}}{{H}_{6}}{{O}_{4}}A\xrightarrow{\Delta }{{C}_{3}}{{H}_{6}}{{O}_{2}}B\xrightarrow[\Delta ]{soda\lim e}C\] Compound C is a hydrocarbon, occupying approx 0.75 L volume per gram. Identify A and B.

A) Tartaric acid, propanoic acid

B) Succinic acid, succinic anhydride

C) Maleic anhydride, maleic acid

D) Methyl malonic acid, propanoic acid

Correct Answer: D

Solution :

\[\underset{A}{\mathop{{{C}_{4}}{{H}_{6}}{{O}_{4}}}}\,\xrightarrow{\Delta }\underset{B}{\mathop{{{C}_{3}}{{H}_{6}}{{O}_{2}}}}\,\] From above equation, it is clear that \[\text{C}{{\text{O}}_{\text{2}}}\]is lost due to heating. Thus, A is a dibasic acid with two -COOH groups on same carbon atom (gem position). Thus, A is For 1 mole of C again,\[\text{C}{{\text{H}}_{\text{3}}}\text{C}{{\text{H}}_{\text{3}}}\] \[(mol\,wt\,=30)\] \[\because \] 30 g of C occupies volume = 22.42 \[\therefore \]1 g of C with occupy volume \[\frac{22.4}{30}\]                                                                 \[\simeq 0.75\,L\]