54 LABOEATOEY MANUAL 



Apparatus 



Iron wool Acid potassium oxalate 



Iron filings Acetic acid 



Magnet Ammonium hydroxide 



Beaker Sulphuric acid 

 Oxalic acid 



Directions: A. Place some of the iron filings on a 

 piece of paper. Slowly bring the magnet in contact 

 with the filings. Raise the magnet. Are there filings 

 attached to it? Are other things attracted to it in the 

 same way? To answer this question try the magnet 

 on a silver coin, a penny, a pin, a piece of gold, etc. 



Moisten some iron wool and set it aside in a beaker 

 for forty-eight hours. What is the appearance of the 

 iron wool at the end of that time? 



Do you know what this reddish deposit is? This is 

 a compound which iron forms with the oxygen of the 

 air in the presence of moisture. From your general 

 observations Avhat other properties of iron could you 

 add to this list? 



B. Linen, cotton, and other textiles frequently 

 become soiled with such a reddish deposit, and a "rust 

 stain" results. Being insoluble in water and alkalies, 

 such stains are not removed by the ordinary washing 

 processes. However, rust or iron oxide is converted 

 to a soluble salt by the action of suitable acids. 



Stain several pieces of white cotton cloth with iron 

 rust. This may be done by placing moistened iron 

 filings on the cloth and leaving them for about thirty 



