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Description
The programme is introduced by Prof. Haynes who shows the student a white crystalline substance. This is MI, an Iodide of an unknown group M. This behaves very much like an alkali metal iodide - bu...t what is it? Dr. Harding examines the X-ray powder pattern produced by MI. This leads to a confusing conclusion about the size of M. Dr. Johnson carries out further cnemical tests which eventually reveal that M is, in fact, the ammonium ion. Dr. Mason shows how one could use infra-red spectra to prove that the gas liberated when MOH is heated is ammonia. The programme continues with an examination of the ways in which ammonium compounds decompose. These are found to fall into two classes : 1. Hydrogen transfer reactions 2. Internal Redox reactions. The programme ends with an experiment to prepare ammonium metal using- the sort of electrolytic cell that can be used to make sodium metal.
The programme is introduced by Prof. Haynes who shows the student a white crystalline substance. This is MI, an Iodide of an unknown group M. This behaves very much like an alkali metal iodide - bu...t what is it? Dr. Harding examines the X-ray powder pattern produced by MI. This leads to a confusing conclusion about the size of M. Dr. Johnson carries out further cnemical tests which eventually reveal that M is, in fact, the ammonium ion. Dr. Mason shows how one could use infra-red spectra to prove that the gas liberated when MOH is heated is ammonia. The programme continues with an examination of the ways in which ammonium compounds decompose. These are found to fall into two classes : 1. Hydrogen transfer reactions 2. Internal Redox reactions. The programme ends with an experiment to prepare ammonium metal using- the sort of electrolytic cell that can be used to make sodium metal.
| Item code: | S25-; 06 |
|---|---|
| First transmission date: | 08-04-1972 |
| Published: | 1972 |
| Rights Statement: | |
| Restrictions on use: | |
| Duration: | 00:24:15 |
| + Show more... | |
| Producer: | Barrie Whatley |
| Contributors: | Charles Harding; Len Haynes; David Johnson; Joan Mason |
| Publisher: | BBC Open University |
| Keyword(s): | Ammonium compound decomposition; Ammonium metal; Electrolytic cell; Hydrogen transfer reactions; Infra-red spectra; Internal Redox reactions; MI iodide investigation; X-ray powder pattern |
| Footage description: | Len Haynes introduces the programme. He shows a white substance, an iodide of an unknown group M and explains that the programme will analyse this substance. Charlie Harding compares X-ray diffraction powder photographs of several alkali metal iodides with one of the M iodide. This, however, leads to a confusing conclusion about the size of M. David Johnson performs several chemical tests with the M iodide and alkali metal iodides. He tests for: 1. ions in the aqueous solution 2. solubility of perchlorates. 3. solubility of the hydroxide and 4. with HC1 testing the gas given off from the aqueous hydroxide. This suggested that the gas was ammonia and the M iodide an ammonium iodide. Joan Mason demonstrates and explains the use of infrared spectroscopy to prove that the gas liberated when an M hydroxide is heated is ammonia. She compares the spectrograph obtained with a standard spectrograph for ammonia. The two are identical. David Johnson demonstrates a floton-transfer reaction. He heats ammonium chloride in a test tube. It vaporises easily. Johnson does the experiment again, this time testing the gas being driven off with litmus paper. Commentary by Johnson for both experiments. This is ionium. Johnson next demonstrates an internal redox reaction. He heats ammonium nitrite. NH₄NO₂ (This is prepared by heating sodium nitrite with ammonium sulphate). Commentary by Johnson explains what is happening. The equation for this reaction is shown on a mag-board. Joan Mason demonstrates another internal redox reaction, the decomposition of ammonium dichroma by heating. She then explains why the decomposition of ammonium perchlorate (NH₄ClO₄) would be an ideal reaction for solid fuel rocket motors. She has in the studio a model of a rocket motor. Johnson sums up the details of the two kinds of decomposition reactions for ammonium salts - proton transfer and internal redox. He explains why alkali metal compounds have no ammonium analogues. The programme ends with an experiment by Johnson to prepare an ammonium metal using an electrolytic cell of the type that is used to make sodium metal. He concludes that an ammonium metal would be highly unstable. |
| Master spool number: | 6LT/70337 |
| Production number: | 00521_2168 |
| Videofinder number: | 1774 |
| Available to public: | no |
