Question

As algae photosynthesize, how will the pH of the CO₂ indicator change? How will the pH change if the cells begin to respire?

Answer 1

Algae photosynthesis raises the pH by consuming CO₂, while algae respiration lowers the pH by producing CO₂.

Step-by-step explanation:

When algae photosynthesize, the pH of the CO₂ indicator will increase (become more basic) as CO₂ is consumed. During respiration, the pH will decrease (become more acidic) as CO₂ is produced.

Algae perform photosynthesis, where they use carbon dioxide and sunlight to produce energy and release oxygen, which in turn reduces the amount of CO₂ in the water. This reduction in CO₂ causes a decrease in hydrogen ion (H+) concentration, leading to an increase in pH (alkaline condition). When algae switch to respiration, typically when there's insufficient light, they consume oxygen and produce carbon dioxide. As CO₂ is released, it reacts with water forming carbonic acid, increasing the H+ concentration, which lowers the pH level (acidic condition).