Q. Which compound is used in photography?
A) $Na_{2}SO_{5}$
B) $Na_{2}S_{2}O_{8}$
C) $Na_{2}S_{2}O_{6}$
D) $Na_{2}S_{2}O_{3}$
Explanation
(d)
Hypo or sodium thiosulphate $\left( Na_{2}S_{2}O_{3} \right)$ is used in the fixing of image. It dissolves unaffected AgBr but leaves metallic silver unchanged.
$2Na_{2}S_{2}O_{3} + AgBr\ \rightarrow Na_{3}\left\lbrack Ag\left( S_{2}O_{3} \right)_{2} \right\rbrack + NaBr$
Hypo soluble
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.