MCQ
In photography sodium thiosulphate is used as
  • Complexing agent
  • B
    Oxidising agent
  • C
    Reducing agent
  • D
    None of these

Answer

Correct option: A.
Complexing agent
a
(a)In order to make the image permanent, it is necessary to remove the unreduced silver bromide from the surface of the developed film. This operation is called fixing of image. Fixing is done by dipping the developed film or plate in sodium thiosulphate (hypo) solution. the hypo solution dissolves the unreduced silver bromide by forming a complex.

$AgBr + 2N{a_2}{S_2}{O_3} \to \mathop {\mathop {N{a_3}[Ag{{({S_2}{O_3})}_2}]}\limits_{{\rm{Sodium \,argento\,thiosulphate}}} }\limits_{{\rm{(soluble)}}} + NaBr$

Thus sodium thiosulphate acts as a complexing agent.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free