The Electrolysis Investigation - To find out what aspects (if any) of electrolysis are affected by the depth of immersion of the electrodes

The Electrolysis Investigation

Aim:

To find out what aspects (if any) of electrolysis are affected by the depth of immersion of the electrodes.

Hypothesis:

I predict that the rate of reaction will be depending on the length of the carbon electrode immersed in the electrolyte (Sodium Bromide in our case). I think the more deeper the electrode is immersed the faster the rate of reaction will be and visa versa. I believe in this because of the collision theory; according to the collision theory the more surface area something has the faster the reaction will occur since there is more surface area for the successful collisions to occur (keeping in mind that electrolysis isn‘t a reaction in that sense).

Method:

After all the apparatus was collected (See Fig 1.2) a small beaker (80cm) and a small measuring cylinder(8cm) for collecting the Hydrogen produced were filled with the electrolyte: Sodium Bromide (NaBr). Then the measuring cylinder filled with the electrolyte was turned upside down and carefully placed inside the beaker filled with the electrolyte (making sure no air bubbles formed at the top of the measuring cylinder since this would affect the results in an negative way). After completing these steps one special hook type copper electrode (copper tip with insulation around it ) was placed into the beaker and then the upside down measuring cylinder with the electrolyte was placed on top of the un-insulated copper tip of the electrode. Then a power – pack (9V) with an ammeter connected in series was attached to both the electrodes (hook-type electrode was a constant and another normal straight electrode, which was the variable changed in this experiment), however leaving the normal electrode outside the beaker. Then a stop watch and a sheet of paper were collected for recording the results; after that the normal electrode was measured (1st exp.= 1cm, 2nd exp. = 1.5, 3rd exp. = 2cm, 4th exp. = 2.5cm and last but not least the 5th exp.= 3cm) and then immersed into the electrolyte (the timing started from the point the so called normal electrode got into contact with the electrolyte). Every 1 minute the amount of Hydrogen produced (recorded from the upside down measuring cylinder) and the current were measured (recorded from the Ammeter) for a total of 15 minutes as these were the aspects that were supposed to be affected by the depth of immersion of the electrode (one because the hook shaped electrode had insulation on and therefore the surface area any way would not changed making only the other electrode the variable). Altogether five experiments (1cm, 1.5cm, 2cm, 2.5cm and 3 cm) were done to obtain a variety and reliable results.

Conclusion:

From Fig.1.4 and Fig.1.6 it can be clearly seen that the current and the rate of hydrogen collected are two aspects of electrolysis that are affected by the depth of immersion, of the electrodes.

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Conclusion:

From Fig.1.4 and Fig.1.6 it can be clearly seen that the current and the rate of hydrogen collected are two aspects of electrolysis that are affected by the depth of immersion, of the electrodes.

From Fig. 1.4 it can be quite easily seen that when the depth of immersion of the electrode increases the current in Amps also increases quite proportionally (for the 2 cm experiment the reading is not incorrect but seems as as if and this is because you don‘t see a significant change from 1.5 cm – 2 cm since the Ammeter was not digital it is very difficult to tell how much the current actually was) and visa versa. This is due to the fact that when the surface area of an electrode increases there is also an increase in the number of e- flowing past a point in one second (that is what the ammeter actually measures) since more e- can leave the electrode and flow into the electrolyte at the same time, there is a faster reaction (even though I am keeping in mind that electrolysis isn‘t really a reaction in that sense), which brings me to the second aspect tested in this specific experiment.

Evaluation:

In all experiments there are always a few improvements that can be made to get even better and reliable results than the ones obtained from the previous one. There was one very obvious anomalic result in this experiment that can be seen from Fig.1.5 and 1.6. For the experiment, in which one of the electrode was immersed 3 cm into the electrolyte the results showed that the rate of reaction was even slower than the one of 2.5 cm and even 2 cm, which surely does not make any sense at all and would contradict with all the theories mentioned before. The reason why that specific result is an anomaly in this experiment can have many reasons but some of the plausible reasons might be as followed: the concentration of the electrolyte was different (maybe someone else diluted it by mistake), the amount of the electrolyte might have been less than the other ones and the timing might have been incorrect (too fast perhaps).

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