question_answer

Sodium salt of an organic acid 'X' produces effervescence with conc. \[{{\text{H}}_{\text{2}}}\text{S}{{\text{O}}_{\text{4}}}\text{.}\]'X' reacts with the acidified aqueous \[\text{CaC}{{\text{l}}_{\text{2}}}\] solution to give a white precipitate which decolourises acidic solution of \[\text{KMn}{{\text{O}}_{4}}.\] 'X' is :-     JEE Main Solved Paper-2017

A) \[{{C}_{6}}{{H}_{5}}COONa\]     

B) \[HCOONa\]

C) \[CH3COONa\]

D) \[N{{a}_{2}}{{C}_{2}}{{O}_{4}}\]

Correct Answer: D

Solution :

 \[N{{a}_{2}}{{C}_{2}}{{O}_{4}}+\underset{\text{conc}\text{.}}{\mathop{{{H}_{2}}S{{O}_{4}}}}\,\xrightarrow{{}}N{{a}_{2}}S{{O}_{4}}+CO\uparrow \]            \[+C{{O}_{2}}\infty \uparrow +{{H}_{2}}O\]\[N{{a}_{2}}{{C}_{2}}{{O}_{4}}+CaC{{l}_{2}}\xrightarrow{{}}\underset{(white\,ppt.)}{\mathop{Ca{{C}_{2}}{{O}_{4}}}}\,\downarrow 2NaCl\]