What could X2 be? and that could the colour of Y^- be?
A) chlorine / brown
B) chlorine / colourless
C) iodine / brown
D) iodine / colourless
the answer should be B, but how, I reckon if X displaced Y (it did right?), then it must be more reactive, hence it has a lighter colour (as we go down group 7 elements, they get darker in colour) that made me choose A as an answer, which is incorrect :-(
Any explanation would be very much appreciated http://www.chemistryhelpforum.com/ch...lies/smile.gif