JAMB - Chemistry (2009 - No. 20)
The colour changes observed when testing for reducing agents using acidified potassium heptaoxodichromate (VI) solution is?
yellow to purple
orange to green
green to orange
purple to yellow
Explanation
Reducing agent like SO\(_2\).
Sulphur dioxide gas (SO\(_2\)) is bubbled through acidified potassium dichromate. The orange solution turns green.