Cyanotype is a photographic printing process .The salt used in this process is
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sodium chromate
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potassium dichromate
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potassium ferricyanide
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cobalt(II) chloride
C
Correct answer
Explanation
Potassium ferricyanide is the chemical compound with the formula K3[Fe(CN)6]. This bright red salt contains the octahedrally coordinated [Fe(CN)6]3− ion. The compound has widespread use in blueprint drawing and in photography (Cyanotype process). Potassium ferricyanide is used as an oxidizing agent to remove silver from negatives and positives, a process called dot etching.