Electrolysis predicting products

The electrolysis of water requires the lowest external voltage. Therefore, the predicted products of this electrolysis are hydrogen and oxygen. 

Using your knowledge of electrolysis, predict the likely products of the electrolysis of copper(n) chloride solution, using platinum electrodes. Write electrode equations for the formation of these products. 

In this part of Chapter 12, we study electrolysis, the process of driving a reaction in a nonspontaneous direction by using an electric current. First, we see how electrochemical cells are constructed for electrolysis and how to predict the potential needed to bring electrolysis about. Then, we examine the products of electrolysis and see how to predict the amount of products to expect for a given flow ot electric current. 

Sei e-Test 12.13A Predict the products resulting from the electrolysis of l M AgNOj(aq). 

Predict the likely products of electrolysis of an aqueous solution from standard potentials (Example 12.1 I). 

A radical tandem cyclization, consisting of two radical carbocyclizations and a heterocoupling reaction, has been achieved by electrolysis of unsaturated carboxylic acids with different coacids. This provides a short synthetic sequence to tricyclic products, for example, triquinanes, starting from carboxylic acids which are accessible in few steps (Scheme 6) [123]. The selectivity for the formation of the tricyclic, bi-cyclic, and monocyclic product depending on the current density could be predicted by applying a mathematical simulation based on the proposed mechanism. 

The comparison of the Daniell cell with the electrolytic version of the cell appears straightforward. One reaction is the reverse of the other. However, you have just learned that the electrolysis of an aqueous solution may involve the electrolysis of water. How can you predict the actual products for this type of electrolysis reaction ... 

To predict the products of an electrolysis involving an aqueous solution, you must examine all possible half-reactions and their reduction potentials. Then, you must find the overall reaction that requires the lowest external voltage. That is, you must find the overall cell reaction with a negative cell potential that is closest to zero. The next Sample Problem shows you how to predict the products of the electrolysis of an aqueous solution. 

Predict the products of the electrolysis of a 1 mol/L solution of sodium chloride. 

In Investigation 11-B, you will build an electrolytic cell for the electrolysis of an aqueous solution of potassium iodide. You will predict the products of the electrolysis, and compare the observed products with your predictions. 

What are the products from the electrolysis of a 1 mol/L aqueous solution of potassium iodide Are the observed products the ones predicted using reduction potentials ... 

Use the relevant standard reduction potentials from the table in Appendix E, and the non-standard reduction potentials you used previously for water, to predict the electrolysis products. Predict which product(s) are formed at the anode and which product(s) are formed at the cathode. 

Predict the products that would be expected from the electrolysis of 1.0 mol/L Nal. Use the nonstandard E values for water. 

For this section, yield of the head-to-head product is relevant. In DMF with 0.1 M of tetra-butylammonium perchlorate, electrolysis of acetophenone at the potential of the first one-electron wave produces this dimer in 30% yield. This is in accord with the earlier-mentioned prediction that all the three directions of this dimerization are equally probable. If lithium perchlorate is the supporting electrolyte in the same solution, the head-to-head dimer yield rises to 70% (GuTtyai et al. 1987a). Hence, head-to-head coupling becomes the main route of dimerization. 

Onda K, Kyakuno T, Hattori K, Ito K (2004) Prediction of production power for high-pressure hydrogen by high-pressure water electrolysis. J Power Sources 132 64-70... 

Predict the products of electrolysis of a solution of copper(n) sulfate if carbon electrodes are used instead of those made from copper as referred to in the purification of copper section. 

It follows from Equation 6.12 that the current depends on the surface concentrations of O and R, i.e. on the potential of the working electrode, but the current is, for obvious reasons, also dependent on the transport of O and R to and from the electrode surface. It is intuitively understood that the transport of a substrate to the electrode surface, and of intermediates and products away from the electrode surface, has to be effective in order to achieve a high rate of conversion. In this sense, an electrochemical reaction is similar to any other chemical surface process. In a typical laboratory electrolysis cell, the necessary transport is accomplished by magnetic stirring. How exactly the fluid flow achieved by stirring and the diffusion in and out of the stationary layer close to the electrode surface may be described in mathematical terms is usually of no concern the mass transport just has to be effective. The situation is quite different when an electrochemical method is to be used for kinetics and mechanism studies. Kinetics and mechanism studies are, as a rule, based on the comparison of experimental results with theoretical predictions based on a given set of rate laws and, for this reason, it is of the utmost importance that the mass transport is well defined and calculable. Since the intention here is simply to introduce the different contributions to mass transport in electrochemistry, rather than to present a full mathematical account of the transport phenomena met in various electrochemical methods, we shall consider transport in only one dimension, the x-coordinate, normal to a planar electrode surface (see also Chapter 5). 

In the continued electrolysis of each of the following solutions at pH 7.0 and 25°C, predict the main product at each electrode if there are no (irreversible) electrode polarization effects (a) 1 M NiS04 with palladium electrodes (b) 1M NiBr2 with inert electrodes (c) 1M Na2SC>4 with Cu electrodes. 

Predict the principal product at each electrode in the continued electrolysis at 25°C of each of the following (a) 1 M... 

On the basis of the preceding generalizations, it is possible to predict the products of electrolysis of aqueous solutions of simple salts. It is not... 

The rate of electrodeposition is dependent on a number of factors, and these are predictable to only a limited degree. However, the thickness of the diffusion layer must be minimized to obtain a rapid electrolysis. This is accomplished by vigorously stirring and by the use of electrodes with large surface areas. An increase in temperature enhances the rate of electrolysis because it increases the mobility of the electroactive species. The use of high ionic concentrations minimizes the iR drop between electrodes and also improves the electrolysis rate. The orientation and geometry of the electrodes is important to insure a uniform and adherent plate. Depolarizers frequently are introduced to prevent formation of interfering products from the counter electrode (see Table 3.5). 

A comparison of the E°s would lead us to predict that the reduction (it) would be favored over that of (i). This is certainly the case from a purely energetic standpoint, but as was mentioned in the section on fuel cells, electrode reactions involving 02 are notoriously slow (that is, they are kinetically hindered), so the anodic process here is under kinetic rather than thermodynamic control. The reduction of water (iv) is energetically favored over that of Na+ (iii), so the net result of the electrolysis of brine is the production of Cl2 and NaOH ( caustic ), both of which are of immense industrial importance ... 

---