Compounds $\mathrm{A}$ and $\mathrm{B}$ are treated with dil. HCl separately. The gas liberated are Y and Z respectively. $\mathrm{Y}$ turns acidified ${\mathrm{K}}_2\mathrm{C}{\mathrm{r}}_2{\mathrm{O}}_7$ paper green while Z turns lead acetate paper black. The compounds $\mathrm{A}$ and $\mathrm{B}$ are respectively.

• A

  $\mathrm{N}\mathrm{a}\mathrm{C}\mathrm{l }\mathrm{}\mathrm{a}\mathrm{n}\mathrm{d }\mathrm{}\mathrm{N}{\mathrm{a}}_2\mathrm{C}{\mathrm{O}}_3$
• Correct answer
  B

  $\mathrm{N}{\mathrm{a}}_2\mathrm{S}{\mathrm{O}}_{\mathrm{3 }}\mathrm{}\mathrm{a}\mathrm{n}\mathrm{d }\mathrm{}\mathrm{N}{\mathrm{a}}_2\mathrm{S}\mathrm{}$
• C

  $\mathrm{N}{\mathrm{a}}_2\mathrm{S }\mathrm{}\mathrm{a}\mathrm{n}\mathrm{d }\mathrm{}\mathrm{N}{\mathrm{a}}_2\mathrm{S}{\mathrm{O}}_3$
• D

  $\mathrm{N}{\mathrm{a}}_2\mathrm{S}{\mathrm{O}}_{\mathrm{3 }}\mathrm{}\mathrm{a}\mathrm{n}\mathrm{d }\mathrm{}\mathrm{N}{\mathrm{a}}_2\mathrm{S}{\mathrm{O}}_4$

Hence, the correct answer is option: 'B'.