Chapter 9, Problem 119A

Interpretation Introduction

Interpretation:

The reactions needs to be explained when Al is placed in KCl and AgNO₃.

Concept introduction:

The reactivity series of metals is as follows:

Lithium > Rubidium > Potassium > Calcium > Sodium > Magnesium > Aluminium > Manganese > Zinc > Iron > Nickel > Tin > Lead > Copper > Silver > Platinum > Gold

Answer to Problem 119A

In the first reaction, aluminium metal is placed in aqueous $\text{KCl}$

$\text{Al}\left(\text{s}\right)\text{+}\text{KCl}\left(\text{aq}\right)\to \text{NR}$

In this reaction, potassium is more reactive than aluminium according to the reactivity series of metals. Therefore, aluminium will not displace potassium and hence, the reaction will not proceed.

In the second reaction, another piece of aluminium is placed in an aqueous ${\text{AgNO}}_{\text{3}}$ solution.

$\text{Al}\left(\text{s}\right)\text{+}{\text{3AgNO}}_{\text{3}}\left(\text{aq}\right)\to \text{3Ag}\left(\text{s}\right)\text{+}\text{Al}{\left({\text{NO}}_{\text{3}}\right)}_{\text{3}}$

In this reaction, aluminium is more reactive than silver. Therefore, aluminium will displace silver in the solution and hence the reaction will proceed.

Explanation of Solution

The reactivity series of metals is as follows:

Lithium > Rubidium > Potassium > Calcium > Sodium > Magnesium > Aluminium > Manganese > Zinc > Iron > Nickel > Tin > Lead > Copper > Silver > Platinum > Gold

The metal higher on the series is the most active and will not be precipitated. The metal lower on the series is less active and hence will be precipitated.

In the first reaction, aluminium metal is placed in aqueous $\text{KCl}$

$\text{Al}\left(\text{s}\right)\text{+}\text{KCl}\left(\text{aq}\right)\to \text{NR}$

In this reaction, potassium is more reactive than aluminium according to thereactivity series of metals. Therefore, aluminium will not displace potassium and hence, the reaction will not proceed.

In the second reaction, another piece of aluminium is placed in an aqueous ${\text{AgNO}}_{\text{3}}$ solution.

$\text{Al}\left(\text{s}\right)\text{+}{\text{3AgNO}}_{\text{3}}\left(\text{aq}\right)\to \text{3Ag}\left(\text{s}\right)\text{+}\text{Al}{\left({\text{NO}}_{\text{3}}\right)}_{\text{3}}\left(aq\right)$

In this reaction, aluminium is more reactive than silver. Therefore, aluminium will displace silver in the solution and hence the reaction will proceed.

Conclusion

In the first reaction, $\text{Al}\left(\text{s}\right)\text{+}\text{KCl}\left(\text{aq}\right)\to \text{NR}$, potassium is more reactive than aluminium according to the reactivity series of metals. Therefore, aluminium will not displace potassium and hence, the reaction will not proceed.

In the second reaction, $\text{Al}\left(\text{s}\right)\text{+}{\text{3AgNO}}_{\text{3}}\left(\text{aq}\right)\to \text{3Ag}\left(\text{s}\right)\text{+}\text{Al}{\left({\text{NO}}_{\text{3}}\right)}_{\text{3}}$, aluminium is more reactive than silver. Therefore, aluminium will displace silver in the solution and hence the reaction will proceed.