Over the centuries, Wally Rhinoceros has been doing fiendish
experiments in his lab coat and carved these original questions
into slabs of ice,
Do drop a line to Wally Rhinoceros
for friendly hints/tips in answering these questions. If you send in some
correct answers he might even send you a list of his favourite Stone-Age web sites!
1. From the description, suggest identities for the compunds D, E & F
and explain the reactions involved:
(i) Powder D turned black when heated gently. The residue dissolved in dilute sulphuric acid
without effervescence. When ammonia solution was added, a pale blue precipitate formed,
which dissolved when further ammonia was added.
(ii) Dark crystals of E dissolve in water to a purple solution which is rendered colourless
by the addition of sodium thiosulphate.
(iii) Separate portions of an aqueous solution of F were used for three tests:
- Addition of barium chloride solution gave a white precipitate insoluble in
dilute hydrochloric acid.
- reaction with magnesium ribbon gave a flammable gas.
- A nichrome wire dipped into the solution gave a bright yellow colour in a flame.
1. How would you synthesise chromyl chloride (CrO2Cl2)?
What precautions might you take? Is it likely to be a liquid or a solid at ordinary temperatures,
and what is its likely colour?
If you prefer other subjects, why not try his friends
Caveman Colin (maths),
Crown Princess Connie (history),
Terry Dactyl (physics) or
H. Potter (obvious) or
Albert O'Saurus (Art) ?
if anyone wants to make money from them please remember that
Terry lived before anyone heard of copyright, but has
some very fierce friends!