JEE · NEET Previous Year Question

Choose the correct tests with respective observations. (pc)
(A) ${\text{CuSO}}_4$ (acidified with acetic acid) $+K_4\left(\text{Fe}\text{(}\text{CN}{\text{)}}_6\right)\to$ Chocolate brown precipitate.(B) ${\text{FeCl}}_3+K_4\left(\text{Fe}\text{(}\text{CN}{\text{)}}_6\right)\to$ Prussian blue precipitate.(C) ${\text{ZnCl}}_2+K_4\left(\text{Fe}\text{(}\text{CN}{\text{)}}_6\right)$, neutralised with ${\text{NH}}_4\text{OH}\to$ White or bluish white precipitate.(D) ${\text{MgCl}}_2+K_4\left(\text{Fe}\text{(}\text{CN}{\text{)}}_6\right)\to$ Blue precipitate.(E) ${\text{BaCl}}_2+K_4\left(\text{Fe}\text{(}\text{CN}{\text{)}}_6\right)$, neutralised with $\text{NaOH}\to$ White precipitate.
Choose the correct answer from the options given below:

Topic: JEE PYQ

Answer: B. Full step-by-step solution below.