(a) List two gases which are monatomic
(b) Mention one gas which forms:
(i) dense white fumes with ammonia vapour
(ii) yellow precipitate with ammoniacal silver trioxonitrate (V) solution.
Explanation
(a) Helium or Neon or Argon (i.e. all noble gases)
(b)(i) Hydrogen chloride gas
(ii) Ethyne of propyne or but-1-nye.