Cuprous iodide paste

The procedure given in test 1 can be employed but the PdCla paper is replaced by paper coated with cuprous iodide paste. (The test may also be conducted in the absorption apparatus shown in Fig. 23, page 53). 

Reagent Cuprous iodide paste A solution of 5 g CuSO SHgO in 75 ml water is mixed with a solution containing 5 g NagSOg and 11 g KI in 75 ml water. The resulting colorless precipitate is filtered or centrifuged, well washed with water, and stored moist. Just prior to the test, a little of the cuprous iodide is made into a thin slurry with water. 

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