Tin Compounds and Covalent Character

PURPOSE OP EXPERIMENT Prepare tin(II) iodide, Snl2/ tin(IV) iodide, Snl4, and study some physical and chemical properties of these compounds and of potassium iodide, KI. 

Weigh 1.5 g of iodine, I2, directly into a 50-mL or larger beaker using a beam balance. Do not let iodine touch the weighing pan or an aluminum weighing dish because iodine may react with aluminum on contact. Cover the beaker with a watch glass so that iodine vapor does not diffuse readily into the air. CAUTION Iodine can also be an irritant and cause systemic difficulties however, this is seldom a problem because of its low volatility (vapor pressure, 1 mmHg at 38.7°C). 

Add a few crystals of iodine to the mixture of tin and CH2CI2 by tapping the beaker containing iodine, and immediately restopper the flask. Record what you observe in TABLE 37.lA. 

Swirl the flask gently for 5 to 10. minutes until the CH2CI2 solution takes on a red-brown color. Based on the results from your procedure in PRE-LABORATORY QUESTION 4, what causes the red-brown color  

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