1. would change in number of moles of a reactant lead to the change in rate of reaction?
2. in the titrimetric analysis of the amount of hypochlorite in a sample of bleach, why the starch is added near the end point instead of adding it at the beginning?
3. iodine is produced when chlorine reacts to iodide ion, the colour has changed to brown then why starch is used as an indicator?
F6 CHEMISTRY
2012-01-22 6:28 am
回答 (3)
2012-01-22 10:11 pm
✔ 最佳答案
1. Definitely. This is because when the number of moles of the reactant increases, the number of collisions between the reactants will increase, leading to an increase in the number of effective collisions. Since the rate of reaction is dependent on the bombardment of molecules, the rate of reaction will definitely increase.2. The starch indicator cannot be added at the beginning of the titration as clumps of blue solid may be formed, when starch reacts with iodine. These clumps of blue solid are very difficult to break up and will affect the reaction between iodine and hypochlorite
3. As the color change from colorless to brown is not very significant, it is quite hard to observe the color change and to determine the end point.
參考: Lecture notes
2012-01-22 8:01 am
001: Starch cannot react with hypochlorite ion.
2012-01-22 7:25 am
1yes
2,starch can react with hypochlorite
3the brown colour is difficult to observe.since iodine can make starch turn in blue black,therefor we can determine iodine inside easily.
2,starch can react with hypochlorite
3the brown colour is difficult to observe.since iodine can make starch turn in blue black,therefor we can determine iodine inside easily.
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