Herschel observed that an otherwise colourless solution of _________ in water emitted a blue colour under certain circumstances.

The hydrated nickel(II) ion is A: blue B: yellow C: orange D: colourless E: green

What does the color of gin usually look like? A: Golden B: Amber C: Colourless, transparent D: Red

"Here is a liquid as colourless as water, almost tasteless, quite imperceptible in coffee, wine, or any other beverage." In this sentece, "imperceptibble" means____ . A: indistinguishable B: noticeable C: strong

What do the words “four distinct impressions left blue in the colourless skin” show? A: to show their powerful love B: B to show Catherine’s weak health C: both A and B