posted by Jan .
What is the purpose of adding
zinc chloride in the preparation of starch iodide paste?
Please refer to the procedure below: -
Starch Iodide Paste- Heat 100mL of water in a 250mL beaker to boiling, add a solution of 0.75g of potassium iodide in 5mL of water, then add 2g of zinc chloride dissolved in 10mL of water, and, while the solution is boiling, add, with stirring, a smooth suspension of 5g of soluble starch in 30mL of cold water. Continue to boil for 2 mins, then cool.
ZnCl2 serves as a preservative. See