“\"Chlor-alkali exam questions\" [031] activity post – please hide your replies
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This post was last edited by sunjl1981 on 2013-1-6 at 22:02. To encourage active participation from members, 3 wealth points are given for each correct answer; if a calculation process is provided, or if a proper explanation is given, an additional reward of 3 to 6 wealth points is awarded. I believe it’s not about the quantity, but having a reward is enough. The key is everyone’s active participation (participation brings talent) and progressing together. (Note: Only moderator ratings are valid for this post; other ratings are invalid.) True or False questions: 1. At 25°C, the density of table salt is 2.161 g/L. ( ) 2. In industrial production, heat exchange methods include direct heat exchange, shell-and-tube heat exchange, and regenerative heat exchange. ( ) 3. To remove SO42- from deionized water, an excess amount of the precipitant BaCl2 should be added. ( ) Please hide your replies; ratings will not be given unless replies are hidden. For instructions on how to hide replies, click here: Hiding method. Answer using the same IP; only the first post is valid. Also, be careful when posting; edits are invalid! Thank you all! Answer: Wrong, Right, Wrong # hcbbs
1. At 25°C, the density of table salt is 2.161 g/L. (True) 2. In industrial production, heat exchange methods include direct heat exchange, shell-and-tube heat exchange, and regenerative heat exchange. (False) 3. To remove SO42- from demineralized water, an excess amount of the precipitant BaCl2 should be added. (True)
1. Wrong. The density of table salt at 25°C is 2.165 g/L. 2. Right. 3. Wrong. Barium ions cause greater damage to the membrane
It seems necessary to provide an answer: Question 1: Wrong; the unit is incorrect. It should be kg/l. In fact, this unit does not meet the requirements of national standards – specific gravity has no unit, while density does. It’s possible that there were limitations in formulating this question originally. Additionally, there is controversy over the numbers 2.161 and 2.165, as they represent data from different periods. Question 2: Yes, everyone has no objections. Question 3: Incorrect. During the treatment of brine, an amount of barium chloride that is not excessive is added, and this is done before adding sodium carbonate. Since barium, like calcium and magnesium, is a divalent metal cation, it can also block the ion membranes and diaphragms, affect the efficiency of electrolytic current, and increase the cell voltage. Therefore, during brine treatment, an appropriate amount of barium chloride is used to ensure that the refined brine contains no barium ions.