Chapter U5.18, Problem 6E

Interpretation Introduction

Interpretation: The position of platinum in the activity series is to be determined.

Concept Introduction: Some metals are more active than others. By combining different metals and metal ions, one can experimentally determine which metals are more active than other metals. This gives an activity series in which metals can be arranged in order of their activity. More active metals are placed at the top of the list and less active ones are at the bottom of the list.

Answer to Problem 6E

In the activity series, platinum can be placed below silver and above gold; that is in between silver and gold.

Explanation of Solution

The activity series gives list of metals which are more active than other metals. Metals on top of the list like potassium, sodium, calcium are more active than those lower on the list such as iron, nickel, copper etc. More active metals at the top of the list will always displace less active metals below.

Since platinum is more active than gold it is surely above gold in the activity series. Platinum is less active than silver, so it has to be below silver in the activity series. Since silver is more active than gold, the metals can be arranged with silver on top, platinum in the middle and gold at the bottom of the series.

Conclusion

Gold atoms are very difficult to oxidize, and gold cations are very easy to reduce. That is why gold is found in pure state. It rarely forms compounds with other atoms. Hence gold is placed at the bottom of the activity series.