Multiple choice

Cyanotype is a photographic printing process .The salt used in this process is

  1. sodium chromate

  2. potassium dichromate

  3. potassium ferricyanide

  4. cobalt(II) chloride

Reveal answer Fill a bubble to check yourself
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.