2.43 Describe experiments to investigate the effect of light on net gas exchange from a leaf, using hydrogen-carbonate indicator

As light increases, so does photosynthesis. A hydrogen carbonate indicator, like limewater, is an indicator for CO₂. 

• Normal: orange
• Increase: yellow
• Decrease: purple

• Fill a test tube 1/4 full with HCl. 
• Attach leaf to bung and leave it in there
• Vary light intensity every x minutes
• (Change distance y from leaf)
• Record results
• done