2.2.2. DEGREE OF COLORATION OF LIQUIDS 
2.2.2  溶液的度 
The examination of the degree of coloration of liquids in the range brown-yellow-red is carried out by one of the 2 methods below, as prescribed in the monograph. 
颜在棕-黄-红范围之间的液体，其度检查可根据个论中的规定，选择下述2种方法中的一种来进行。
A solution is colourless if it has the appearance of water R or the solvent or is not more intensely coloured than reference solution B9. 
如果一种溶液的外观与水或指定的溶剂的外观一致，或者其颜不深于棕9号标准比溶液（B9），即可认为它就是无的。
METHOD I
Using identical tubes of colourless, transparent, neutral glass of 12 mm external diameter, co
mpare 2.0 mL of the liquid to be examined with 2.0 mL of water R or of the solvent or of the reference solution (see Tables of reference solutions) prescribed in the monograph. Compare the colours in diffused daylight,viewing horizontally against a white background. 
方法1
取外径为12毫米的无、透明，中性玻璃相同试管2支，一支加2.0ml的供试液体，另一支加2.0ml的水，或专论中所用的溶剂，或标准比溶液（参见对照溶液表）。在自然光下，以白为背景，比较两者的颜。
METHOD II
Using identical tubes of colourless, transparent, neutral glass with a flat base and an internal diameter of 15 mm to 25 mm, compare the liquid to be examined with water R or the solvent or the reference solution (see Tables of reference solutions) prescribed in the monograph, the depth of the layer being 40 mm. Compare the colours in diffused daylight, viewing vertically against a white background.
方法2
取内径为15mm～25mm的无、透明，中性玻璃平底试管2支，一支加供试液体，另一支加水，或专论中所用的溶剂，或标准比溶液（参见对照溶液表）。液层高度约为40mm。在自然光下，以白为背景，比较两者的颜。
REAGENTS
试剂与试液
Primary solutions 
三基溶液
Yellow solution. Dissolve 46 g of ferric chloride R in about 900 mL of a mixture of 25 mL of hydrochloric acid R and 975 mL of water R and dilute to 1000.0 mL with the same mixture.
Titrate and adjust the solution to contain 45.0 mg of FeCl3·6H2O per millilitre by adding the same acidic mixture. Protect the solution from light.
黄溶液的制备：取氯化铁46g，加900ml的盐酸溶液（1→40）使溶解，并用该盐酸溶液稀释到1000ml。
滴定该溶液，并加适量盐酸溶液（1→40）进行调节，使 FeCl3·6H2O的含量约为45.0 mg/ml。
将溶液避光保存。
Titration. Place in a 250 mL conical flask fitted with a ground-glass stopper, 10.0 mL of the solution, 15 mL of water R,5 mL of hydrochloric acid R and 4 g of potassium iodide R,close the flask, allow to stand in the dark for 15 min and add 100 mL of water R. Titrate the liberated iodine with 0.1 M sodium thiosulfate, using 0.5 mL of starch solution R, added towards the end of the titration, as indicator. 
1 mL of 0.1 M sodium thiosulfate is equivalent to 27.03 mg of FeCl3·6H2O.  
滴定。取一个250 mL的带磨口玻璃瓶塞的锥形瓶，加入10.0ml该溶液，15ml水，5ml盐酸和4g碘化钾，塞紧瓶盖，在暗处放置15min，加100ml水，用硫代硫酸钠滴定液（0.1mol/L）滴
定析出的碘，在滴定近终点时加入0.5ml淀粉指示剂，以蓝消失为滴定终点。
每1ml的硫代硫酸钠溶液（0.1mol/L）相当于27.03mg的FeCl3·6H2O。
Red solution. Dissolve 60 g of cobalt chloride R in about 900 mL of a mixture of 25 mL of hydrochloric acid R and 975 mL of water R transparent中文意思and dilute to 1000.0 mL with the same mixture. Titrate and adjust the solution to contain 59.5 mg of CoCl2·6H2O per millilitre by adding the same acidic mixture.
红溶液的制备：取氯化钴60g，加900ml的盐酸溶液（1→40）使溶解，并用该盐酸溶液稀释到1000ml。
滴定该溶液，并加适量盐酸溶液（1→40）进行调节，使 CoCl2· 6H2O的含量约为59.5 mg/ml。
Titration. Place in a 250 mL conical flask fitted with a ground-glass stopper, 5.0 mL of the solution, 5 mL of dilute hydrogen peroxide solution R and 10 mL of a 300 g/L solution of sodium hydroxide R. Boil gently for 10 min, allow to cool and add 60 mL of dilute sulfuric ac
id R and 2 g of potassium iodide R. Close the flask and dissolve the precipitate by shaking gently. Titrate the liberated iodine with 0.1 M sodium thiosulfate, using 0.5 mL of starch solution R, added towards the end of the titration, as indicator. The end-point is reached when the solution turns pink.
1 mL of 0.1 M sodium thiosulfate is equivalent to 23.79 mg of CoCl2·6H2O.
滴定。取一个250 mL的带磨口玻璃瓶塞的锥形瓶，加入5.0ml该溶液，5ml稀过氧化氢溶液，10ml的氢氧化钠溶液（300 g/L）。缓缓煮沸10分钟，冷却并加60 mL稀硫酸和2g碘化钾。塞紧瓶盖，轻轻振摇使沉淀物溶解。用硫代硫酸钠滴定液（0.1mol/L）滴定析出的碘，在滴定近终点时加入0.5ml淀粉指示剂，以溶液呈现粉红时作为滴定终点。
每1ml的硫代硫酸钠溶液（0.1mol/L）相当于23.79mg的CoCl2·6H2O。
Blue primary solution. Dissolve 63 g of copper sulfate R in about 900 mL of a mixture of 25 mL of hydrochloric acid R and 975 mL of water R and dilute to 1000.0 mL with the same mixture. Titrate and adjust the solution to contain 62.4 mg of CuSO4·5H2O per millilitre by adding the same acidic mixture.
蓝溶液的制备：取硫酸铜约63g，加900ml的盐酸溶液（1→40）使溶解，并用该盐酸溶液稀释到1000ml。
滴定该溶液，并加适量盐酸溶液（1→40）进行调节，使 CuSO4· 5H2O的含量约为62.4 mg/ml。
Titration. Place in a 250 mL conical flask fitted with a ground-glass stopper, 10.0 mL of the solution, 50 mL of water R,12 mL of dilute acetic acid R and 3 g of potassium iodide R.Titrate the liberated iodine with 0.1 M sodium thiosulfate,using 0.5 mL of starch solution R, added towards the end of the titration, as indicator. The end-point is reached when the solution shows a slight pale brown colour.

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