# Why is activity of solvated components equal to 1?

• crick
In summary, the given reaction involves the formation of nickel and sulfur solid, along with the release of two protons in aqueous solution. The activities of the solvated components, Ni2+ and H+, are defined as 1 in the standard state, which can be achieved by preparing a solution with appropriate concentrations. However, the formation of a mixture of elements rather than a compound seems unusual without further context.
crick

## Homework Statement

Consider the following reaction

$$\mathrm{Ni^{2+}_{(aq)} + H_2S_{(g)} \to Ni_{(s)} + S_{(s)} + 2H^{+}_{(aq)}}$$

What are the activities of the terms in the reaction?

## Homework Equations

The activity is defined as ##a = c/c^\circ## in ##\mathrm{ mol \, dm^3}##

3. The Attempt at a Solution

I do not understand why textbook gives ##a_\mathrm{Ni^{2+} (aq)} =1## and ##a_\mathrm{2H^{+} (aq)} =1##: how can I say that those activities are ##1##? Is there a rule to understand activites of solvated compontents (aq)?

It is not always possible, but you can rather easily prepare a solution containing Ni2+ and H+ in such concentrations that their activities equal 1. Makes sense as it is a standard state used as a reference point.

Something is wrong here, but it is hard to judge without a context. I would expect NiS(s) as a product, not mixture of elements.

## 1. Why is it important for the activity of solvated components to be equal to 1?

The activity of solvated components being equal to 1 is important because it signifies ideal behavior in a solution. This means that the components are behaving as predicted by theoretical models and their concentrations can be directly related to their activities, simplifying calculations and predictions.

## 2. What factors affect the activity of solvated components?

The activity of solvated components can be affected by factors such as temperature, pressure, and the presence of other solutes in the solution. These factors can alter the interactions between the solvated components, leading to deviations from ideal behavior.

## 3. How is activity related to concentration in a solution?

In an ideal solution, the activity of a solvated component is equal to its concentration. However, in non-ideal solutions, the activity and concentration may not be directly proportional due to factors such as interactions between solutes and the presence of non-solvated species.

## 4. Can the activity of solvated components ever be greater than 1?

No, the activity of solvated components can never be greater than 1. This would indicate a deviation from ideal behavior and could be caused by factors such as interactions between solutes or a non-ideal solvent.

## 5. How is the activity coefficient related to the activity of solvated components?

The activity coefficient is a measure of how the activity of a solvated component differs from its concentration in a non-ideal solution. It is used in calculations to correct for deviations from ideal behavior and is directly related to the activity of solvated components in the solution.

Replies
1
Views
3K
Replies
9
Views
352
Replies
2
Views
5K
Replies
5
Views
2K
Replies
9
Views
6K
Replies
16
Views
5K
Replies
3
Views
13K
Replies
2
Views
1K
Replies
5
Views
3K
Replies
1
Views
1K