Peroxides occur in a wide variety of situations: organic peroxides, having the general formula ROOR, where R
is an organic group, are often used to start polymerization reactions, such as the ones needed to make
commonly occurring polymers like polystyrene and polythene.
Hydrogen peroxide, HB2BOB2B is readily available in supermarkets and pharmacies since it is a principal
component in bleaches for hair and most recently and controversially it was one of the components used to
make the bombs which exploded in London on 7PthP July 2005.
Peroxides are also thought to contribute to aging of skin and they are also a source of free radicals thought to
be partly responsible for some cancers.
In this experiment you will use a titrimetric method to determine the amount of hydrogen peroxide in a given
solution. Hydrogen peroxide can act as both an oxidizing agent and a reducing agent depending upon the
conditions of the reaction. In this experiment hydrogen peroxide will oxidize the iodide ion, IP-P, obtained from
potassium iodide to iodine, IB2B. The iodine produced reacts with sodium thiosulphate and the amount of
thiosulphate required can be used to calculate the amount of iodine present and hence the amount of
hydrogen peroxide in the solution.
Titrimetry, or titrimetric analysis, is an example of a so-called classical method of analysis. Titrimetry is a
convenient method of getting very small amounts of chemicals in to a reaction because the method involves
the use of dilute solutions of reactants.
Hydrogen peroxide reacts with potassium iodide according to the reaction given below:
HB2BOB2B + 2HP+P + 2IP-P = IB2B + 2HB2BO (equation 1)
Equation 1 shows that 1 mole of hydrogen peroxide gives 1 mole of IB2B.
Note: we have omitted the potassium ion, KP+P, from this reaction since it would occur on both sides of the
equation and so it does not take part in the reaction.
The iodine produced reacts with sodium thiosulphate, NaB2BSB2BOB3B as shown in equation 2 below:
IB2B + 2S2O32- 2IP- + S4O6B2- (equation 2)
Equation 2 shows that 1 mole of iodine reacts exactly with 2 moles of thiosulphate.
Combining equations 1 and 2:
1 mole HB2BOB2B gives 1 mole iodine AND 1 mole iodine reacts with 2 moles thiosulphate.
This shows that 1 mole HB2BOB2B is equivalent to 2 moles thiosulphate.
This means that if we know how much (the number of moles) thiosulphate we need to react with the iodine we
can calculate how much hydrogen peroxide was in the solution we started with.
In this experiment you will use titrimetric analysis to determine the concentration of hydrogen peroxide in a
solution. The titration is relatively easy to follow because the iodine produced by reaction of hydrogen peroxide
with iodide is iodine, which is purple in colour. Addition of thiosulphate solution gives a colourless solution when
all of the iodine has reacted (the end point). You can make the end point even sharper by adding a few drops
of starch solution when the colour of the solution is pale yellow. The starch changes the colour of the solution
to black but the solution will become colourless at the end point.
The experiment is quite short and so you have plenty of opportunity to repeat the titrations until you get
You have already carried out an acid-base titration and so you should know that “consistent results” means that
the volumes required to completely decolourise the iodine produced should be consistent to ± 0.1 cmP3P.
You are provided with a solution of hydrogen peroxide and a solution of sodium thiosulphate as well as 1.25
mol dm-3 sulphuric acid and solid potassium iodide.
Throughout your experiment, note any colours that are observed in your lab book.
- Note the concentration of the sodium thiosulphate solution supplied.
0.02497 mol dm-3
- Measure out 5 cmP3 of 1.25 mol dm-3 sulphuric acid using a measuring cylinder and place it in a 250
cmP3P conical flask.
- Add about 0.5 g of potassium iodide. There is NO NEED TO WEIGH THIS ACCURATELY so just use a top
pan balance. Swirl the flask in order to dissolve the potassium iodide in the sulphuric acid.
0.51g, 0.50g, 0.49g, 0.48 g
- When the potassium iodide has all dissolved use pipette and measure out 10.00 cmP3P of the hydrogen
- Gradually add the hydrogen peroxide solution to the acidified potassium iodide solution with constant
- Use a cork, rubber bung or parafilm to close the top of the conical flask and allow the mixture to stand for 15
minutes. The solution should become dark orange/brown because of the presence of iodine in solution.
- Pour sodium thiosulphate into a burette. Run some of this solution through the burette to remove any
bubbles below the tap.
- Record the reading on the burette to the nearest 0.05 cm3 (NOTE: you will have to estimate the second
decimal place). THERE IS NO NEED TO GET THE VOLUME TO EXACTLY 0.00 ON THE BURETTE.
- Titrate the iodine solution in the conical flask with the sodium thiosulphate in the burette. You can add the
thiosulphate fairly quickly in the early stages but you will need to add the thiosulphate more slowly as the
colour of the iodine get more and more yellow.
- When the iodine solution becomes straw coloured (pale yellow) add a few drops of starch solution. The
iodine solution should now be much darker – almost black.
- Continue adding the thiosulphate solution until the iodine solution becomes colourless.
- Record the reading on the burette again to the nearest 0.05 cmP3.P
- The volume of thiosulphate required to react with the iodine solution is the difference between the final
reading and the initial reading.
- Repeat steps 2 – 13 until you get THREE consistent results (i.e. where the volume used agrees to ± 0.1
1 2 3 4
Initial volume (cm3) 1.00 2.00 0.10 0.05
Final volume (cm3) 25.10 25.75 23.75 23.75
volume used (cmP3P)
- Calculate the concentration of hydrogen peroxide in the solution provided.
EVALUATION OF RESULTS
Combining equations 1 and 2 to determine the mole ratio of peroxide to thiosulphate:
1 mole HB2BOB2B gives 1 mole iodine AND 1 mole iodine reacts with 2 moles thiosulphate.
This shows that 1 mole (n2) HB2BOB2B is equivalent to 2 (n1) moles thiosulphate (mole ratio).
C = Concentration (mol dm-3), V = Volume (cm3)
Rearrange C1V1/n1= C2V2/n2 to give C2
- Calculate a value for the concentration of the hydrogen peroxide solution for your best three titrations.
- Calculate the mean, standard deviation and relative standard deviation for your data. (use your best three titrations)
- Comment on your results.
A Leader, or for our situation a Masters Career and the destiny of his vessel and Bridge group are dictated by the viability of his conduct. Administration is viewed as significant for progress and has been considered by most specialists to be the most basic fixing (Lussier and Achua 2009). I would depict a pioneer as being somebody who coordinates and controls a gathering of individuals to play out an errand. For this situation the Master controls and guides his Officers to securely explore the vessel, wellbeing of the group and the payload. Not at all like different organizations who will have numerous pioneers, the Master is the sole head on a vessel whereupon all duty lies on. The manner in which the Master manages every one of his obligations is to delegate to his Officers. Every one of his Officers basically likewise become chiefs of perhaps their own gathering of laborers. The Master drives his supervisors (Officers) to play out the assignments required to keep up the vessel. A significant differentiation is made between being a supervisor and being a pioneer. To be an administrator intends to coordinate and to achieve. To lead intends to persuade and motivate. Pioneers who are successful, rouse their group to endeavor and seek after greatness. It has been said that administrators are individuals who do things right and pioneers are individuals who make the best choice (Peter F.Drucker 1955). For a Master to be a decent pioneer he should have the option to spur his officials adequately. An experts individual components will impact how well he/she rouses the group. I have worked with a couple of Captains each with their very own distinctive initiative styles. No two heads work similarly, every pioneer builds up their own individual style. A portion of the elements that influence a Master may create after some time and experience, while some may create because of their condition for example sort of vessel or extension group. A few Masters may even need to adjust their initiative style to the encompassing condition and to organization necessities. Clearly one of a Masters fundamental individual factor is his/her character. The administration style might be an expansion of the character. I found that two of the four Masters I worked with tend not to impart legitimately to a few. The two Captains that favored the technique for conveying to his group legitimately or up close and personal were all the more cordial and decisive. These Captains additionally appeared to confide in their official more, for instance they once in a while did any of the moves when coming all through port, they permitted the lower positioned officials to take control and were quick to lead and educate. The other two Captains appeared to need to show others how its done as they were progressively held and once in a while came up to the scaffold other than when required. These Captains consistently did moves themselves and favored the progressive strategy. They favored gathering with the following in order as a strategy for correspondence to the lower positions, rather than tending to the whole group. Another individual factor is the degree of control a Master likes to have, which impacts the administration style. The Master has generally control of all choices made on his vessel yet some are more laid back than others. A Master that has an elevated level of control will need to be associated with the entire everyday activities and the basic leadership process. An all the more believing Master may not need the weight of the basic leadership and will make a stride back and delegate duty. As this is the situation on most vessels a Master that delegates his duties will ordinarily need to make another layer of the executives, this duty is typically given to the main mate or second in direction. Another factor that may influence the administration of a Master is simply the Organization or organization. There is a various leveled structure on vessels while there is a divisional structure inside an organization. The organization's structure and working techniques may direct the initiative style that the Master must embrace. The Master must actualize all arrangements that the organization set out and keep up them as checked by evaluators. A Masters understanding, both as a pioneer and time span with a specific organization can influence his administration. A Master who has as of late been elevated might need to lead by the book and pursue all methods to the spot, while they are as yet unpracticed as Masters. A Master who has more involvement with the activity advertisement with the organization may have more certainty by following their own understanding of the guidelines set out by the organization. The more experience a Master has and progressively comfortable they are with the organization will bring about the Master being increasingly open to settling on choices thusly being a viable and certain pioneer. Another hierarchical factor in influencing a Masters authority is his groups' ethnic decent variety. Particularly on traveler vessels which can hang overall more than 1000 team, which can have 55+ various ethnicities. Fortunately for the Masters on traveler vessels an office framework is run so he doesn't need to legitimately manage all 1000+ group. He/She just needs to straightforwardly manage the Deck office and will just need to address his group in any disciplinary activity. Indeed, even on the scaffold there can be a scope of nationalities (from individual experience) To be a fruitful pioneer of numerous nationalities the Master may adopt a hireling strategy, where they give the worker's all that they need with the goal that the group remain spurred and make for powerful cooperation. Maslow's hypothesis shows these requirements in better detail. A Master as a pioneer can just give such a great amount to his group before following the organizations arrangements, which is additionally set out in the ISM code. To finish up there are numerous variables on which a Master needs to adjust to be a powerful pioneer, he/she should consider the necessities of the group (Maslow's hypothesis) while likewise keeping the Organization cheerful by conforming to their principles and strategies. As far as I can tell I have discovered that Masters with successful administration additionally prefer to make a stride back and enable his official to be the principle part of the basic leadership process and believe in his group. Correspondence is a key factor when attempting to finish an activity easily and securely. We impart constantly, it comes normal to us like breathing, yet having the option to convey obviously and with a touch of artfulness is very troublesome, particularly when you may have a worldwide team installed. Locally available the boats I was dealing with we had this issue of an immense assortment of nationalities. Taking a shot at journey ships implies you can have more than 1000 other group to manage. To defeat the issue of language and correspondence the organization set out the approach that the working language be English, and all team must have a decent comprehension of the English language, this incorporates officials too. Working a ton with the deck team who were all either Philippine or Indonesian, I encountered a considerable amount of a language obstruction among them and the Bosun who was Italian. The Bosun was not enthused about communicating in English and attempted to maintain a strategic distance from it however much as could reasonably be expected. In this piece of the work I found that solitary verbal correspondence was utilized to give the employments to the deck group for the afternoon. Under the most favorable circumstances I could scarcely comprehend the Bosun. To enhance this it would be a smart thought to have work rotors posted on a notification board in the workshop so the deck group can without much of a stretch allude to perceive what their employments are for that day and who they are working with. On the scaffold the Officers comprised of British and Italian speakers. Again anything identified with work for example crash evasion promotion crises must be spoken in English. By and by I found that correspondence on the scaffold between the group during activities and moving were without issue. We utilized the shut circle specialized technique, where the individual accepting the requests rehashed them so the official realized he had comprehended the request. While the Captain had by and large charge of the activity, our staff Captain played the job of Operations executive. His activity was to speak with the officials down in the securing stations, who utilized the equivalent shut circle strategy. As there is a chain of command on the extension I found that correspondence between the lower positions and cadets was negligible. I found ordinarily that I would get a vocation or a request from the staff skipper that had advanced down the positions. The issue with this was the activity would get confounded and not the same as the first the more individuals it experienced. This was not purposeful, yet would result at times in the activity being done inaccurately. The undeniable method to improve this issue is for the higher positioning officials to legitimately give the work. Along these lines inquiries can be posed if the errand isn't completely comprehended. While being a piece of securing activities I saw that on occasion there would be a great deal of yelling from either the Officer or the bosun. The explanation behind this was they didn't have the foggiest idea about the name of people in the group, which would bring about the words 'hello' or 'you' being yelled. This caused immense perplexity between the deck team and disappointment for the Bosun or Officer. I saw and proposed to the Officer that perhaps it is great to get familiar with the names of all the deck group. I set aside the effort to get familiar with every one of their names and saw what amount valued it really was. In addition to the fact that they respected you more, correspondence to an individual was far more clear as the individual knew when they were being told. From investing a ton of energy with the deck group I discovered that having their regard is a key factor concerning having the option to give them employments and keeping up inspiration. In end the manner in which I would improve correspondence on my vessel is for the higher positions to be more agreeable and straightforwardly issue orders/work to the lower positions. With regards to correspondence between the deck teams and bosun in securing activities, straightforward things like learning the deck group's names can avert any perplexity and any yelling.>GET ANSWER