Question
Give the points of difference between valency and oxidation number?
Solution
| Valencey | Oxidation Number |
| 1. It is the combining capacity of an element in terms of the number of hydrogen atoms with which the element may combine e.g. valency of S in H2S is 2 and that of N in NH3 is 3. | 1. It is the charge which an atom of the element has or appears to have when present in the combined state with their atoms e.g. oxidation number of N in HNO3 is +5. |
| 2. It is purely a number and has no plus or minus sign associated with it. e.g. valency of N in NH3 is 3 and that of H is 1. | 2. It is always assigned plus or minus sign except when it is zero e.g. oxidation number of N in NH3 is -3 and that of H is +1 |
| 3. It is always a whole number. |
3. It may not always be a whole number but may be fractional also. The e.g. oxidation number of Fe in Fe3O4 is +8/3. |
| 4. It is a real concept which can be verified or determined experimentally. | 4. It is a hypothetical concept. Experimental verification or determination is usually not possible. |
