ISO 731-4:1977

Formic acid for industrial use — Methods of test — Part 4: Visual limit test for inorganic chlorides

Applicable to products having inorganic chlorides contents in the range 0,0005 to 0,5 % (m/m). Comparison of the turbidity, obtained by the addition of silver nitrate to a solution prepared from a test portion, with that similarly obtained from a standard chloride solution.