Question

Which of the following pair of salt produces odourless gas with dil $H_2SO_4$

• A. $HCO^{ -}_3$ and $HSO^{ -}_3$
• B. $HCO^{ -}_3$ and $CO^{ -}_3$
• C. $S_2O^{2 -}_3$ and $CH_3 CO^{ -}_2$
• D. $CO^{2 -}_3$ and $CH_3CO^{ -}_2$

Answer 1

Answer: (B)

$HCO _{3}^{-}$ and $CO _{3}^{-}$ will produce odourless gas i.e.

carbon dioxide with dil. $H _{2} SO _{4}$.

$\underset{\text{Baking soda}}{NaHCO _{3}}( aq )+ H _{2} SO _{4}( aq ) \longrightarrow Na _{2} SO _{4}( aq )+2 CO _{2}( g )+2 H _{2} O ( l )$

$\underset{\text{Washing soda}}{Na _{2} CO _{3}}+ H _{2} SO _{4}( aq ) \longrightarrow Na _{2} SO _{4}( aq )+ H _{2} O ( l )+ CO _{2}( g )$