JEE Main Solved Paper 2017 Question 21

Question: Sodium salt of an organic acid ‘X’ produces effervescence with conc. $ {H_2}S{O_4}\text{.} $ ‘X’ reacts with the acidified aqueous $ CaC{l_2} $ solution to give a white precipitate which decolourises acidic solution of $ KMn{O_4}. $ ‘X’ is :- JEE Main Solved Paper-2017

Options:

A) $ C _6H _5COONa $

B) $ HCOONa $

C) $ CH3COONa $

D) $ Na _2C _2O _4 $

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Answer:

Correct Answer: D

Solution:

  • $ Na _2C _2O _4+\underset{conc\text{.}}{\mathop{H _2SO _4}},\xrightarrow{{}}Na _2SO _4+CO\uparrow $ $ +CO _2\infty \uparrow +H _2O $

$ Na _2C _2O _4+CaCl _2\xrightarrow{{}}\underset{(white,ppt.)}{\mathop{CaC _2O _4}},\downarrow 2NaCl $