Gay Lussac’s of combining volumes states that gases react in simple ratio with one another and to volumes of the products provided that temperature and pressure remain constant. In this article, you will understand how to apply this law in calculation by studying the following examples below: 1. 2H 2 + O 2 → H 2 O In the reaction above, what volume of hydrogen would be left over when 300cm 3 of oxygen and hydrogen are exploded in a sealed tube? 1cm 3 of oxygen = 2cm 3 of hydrogen 300cm 3 of oxygen = 2 x 300 = 600cm 3 Volume of left over = 1000 – 600 = 400cm 3 2. Calculate the volume of carbon (II) oxide required to react with 40cm 3 of oxygen. 2CO + O 2 → 2CO 2 1cm 3 of oxygen = 2cm 3 of CO 40cm 3 of oxygen = 2 x 40 = 80cm 3 3. Calculate the volume of residual gases that would be produced when 100cm 3 of sulphur (IV) oxide reacts with 20cm 3 of oxygen 2SO 2 + O 2 → 2SO 3 1cm 3 of O 2 = 2cm 3 20cm 3 of O 2 = 2 x 20 = 40cm 3
In a qualitative analysis of ions like lead, zinc ions and aluminium ions, these ions show similar reactions with dilute sodium hydroxide solution. They produce white precipitates with a few drops of dilute sodium hydroxide solution, which are soluble in excess dilute sodium hydroxide solution. In this article, you will learn how to separate lead ions from a mixture of aluminium ions and zinc ions. Before I go ahead, let me list some reagents that are necessary for the tests: Aqueous ammonia Dilute hydrochloric acid Potassium dichromate solution Potassium iodide solution Step one: separation of zinc ions from the mixture To the solution of the unknown compounds, add a few drops of aqueous ammonia, and the formation of white gelatinous precipitate that dissolves in excess aqueous ammonia removes lead ions and aluminium ions as an insoluble compound in the excess aqueous ammonia while zinc remains in the solution. Step two: separation of aluminium ions from the mi