Chapter 17, Problem 54A

Interpretation Introduction

Interpretation:

The reason for a soft drink to goes flat when the container is left open needs to be explained.

Concept introduction:

LeChatelier principle states that a system at equilibrium when subjected to changes in the system adjusts it self to attain the equilibrium state again.

Answer to Problem 54A

When the container is left open the acid reaction equilibrium shifts to the right due to a decrease in pressure and the carbonic acid which causes the ‘punch’ in soft drinks decomposes causing the drink to go flat.

Explanation of Solution

Since CO₂ is a gas, reducing the pressure increases its volume which causes its overall concentration to decrease. In the reaction, when the concentration of products decreases the equilibrium shifts to the right forming more product. The amount of carbonic acid decreases causing the drink to go flat.

Conclusion

The soft drink with open container goes flat due to decrease in pressure.