Q. The primary standard solution for estimation of $Na_{2}S_{2}O_{3}$ is
A) $I_{2}$ solution
B) $KMnO_{4}$
C) $K_{2}Cr_{2}O_{7}$
D) Oxalic acid
Explanation
(a)
Standard solution of iodine is used to estimate $Na_{2}S_{2}O_{3}$ (hypo) solution. It is oxidised to sodium tetrathionate by iodine.
$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ 2Na_{2}S_{2}O_{3} + I_{2} \rightarrow Na_{2}S_{4}O_{6} + 2NaI$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.