Question

Reactions can have a wide range of yields. They can produce anything from fractions of percents all the way to almost exactly 100%. The reason that they almost never reach 100% is that almost all reactions are reversible, and once a certain concentration of product is reached, the reaction is no longer favorable.

Hypothesize a way that you could force a reaction to reach 100%. Explain why it would work and why the reverse reaction wouldn’t occur.

Answer 1

To hypothesize how to force a reaction to reach 100% yield, one could remove a product as it forms, preventing the reverse reaction and driving the forward reaction to completion.

Step-by-step explanation:

The question explores why chemical reactions seldom reach a 100% yield and asks for a hypothesis on how to force a reaction to reach 100%. To achieve a complete yield, one could remove one of the products as it forms, shifting the equilibrium towards the product side and driving the reaction to completion. This could include continuous removal of a gaseous product by venting it out, or precipitation of an insoluble product thereby preventing the reverse reaction. The reverse reaction would not occur because the product required for it has been removed from the system, making the process unfavorable in the reverse direction.

Answer 2

Step-by-step explanation:

Let us proceed with a reaction

A(aq)+B(aq)
`\rightleftharpoons` C(aq) + D(g)

Taking A, B and C are in aqueous solution. D being a gas. The reaction is carried out in a close vessel. As reaction proceeds, A and B react to give C and D. As the concentration of C and D increases, they react to give back A and B. Now suppose the reaction is carried out in a open vessel so that the gas D can escape in the atmosphere. So the gas D is no longer available to react with C. So reverse reaction will not occur. The forward reaction is forced to reach 100 %

Let us take another example.

A(aq)+B(aq)
`\rightleftharpoons` C(aq) + D(aq)

Here, D is a volatile liquid. As soon as D is formed, it is removed by distillation. So D is no longer available to react with C. So reverse reaction will not occur. The forward reaction is forced to reach 100 %