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प्रश्न
What is variable valency ? Give two examples of elements showing variable valency.
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उत्तर
Certain elements exhibit more than one valency, that means they show variable valency.
Ferrous is written as Iron (II) and Ferric is written as Iron (III).
| Metal | Radicals | Valency |
| Iron | Ferrous [Iron (II)] Ferric [Iron (III)] |
2 3 |
| Copper | Cuprous [Copper (I)] Cupric [Copper (II)] |
1 2 |
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संबंधित प्रश्न
Write the molecular formula of the following compounds of Iron (II) sulphide and.
Find the number and names of elements present in them and calculate their molecular masses.
Write the molecular formula for the oxide and sulphide of following elements of Hydrogen
The valency of aluminium is 3. Write the valency of other radicals present in the following compounds of Aluminium oxide.
Write the molecular formulae of Iron (III) chloride
Write the molecular formulae of Sodium hydroxide
Write the molecular formulae of Lead (II) oxide – PbO.
Write the molecular formulae of Ammonium carbonate.
Write the chemical formula of the following compound in a step-by-step manner –
Sodium bisulphate
Write the chemical formula of the following compound in a step-by-step manner –
Aluminium hydroxide
Match the compounds in List I – 1 to 20 with their correct formulas in List II – A to T.
| List I | List II |
| 1. Copper [I] sulphide | A: KMnO4 |
| 2. Potassium permanganate | B: Mg3N2 |
| 3. Phosphoric acid | C: Mg(NO3)2 |
| 4. Copper [I] oxide | D: Al2(SO4)3 |
| 5. Carbonic acid | E: Na2ZnO2 |
| 6. Aluminium sulphide | F: N2O |
| 7. Iron [II] oxide | G: H2CO3 |
| 8. Iron [III] sulphide | H: Al2S3 |
| 9. Iron [II] sulphate | I: NO |
| 10. Sodium zincate | J: FeS |
| 11. Nitrous oxide | K: Fe2S3 |
| 12. Aluminium sulphate | L: H3PO4 |
| 13. Magnesium nitride | M: Cu2S |
| 14. Iron [III] sulphate | N: CuS |
| 15. Copper [II] oxide | O: Fe2O3 |
| 16. Iron [III] oxide | P: FeO |
| 17. Nitric oxide | Q: FeSO4 |
| 18. Copper [II] sulphide | R: Fe2(SO4)3 |
| 19. Iron [II] sulphide | S: CuO |
| 20. Magnesium nitrate | T: Cu2O |
