carbon dioxide

• indicator : potassium hydroxide
• potassium hydroxide plants changes no colour on addition of iodine
• potassium hydroxide absorbs carbon dioxide produced during respiration as well as the conical flask. this absorption results in no starch being formed as the colour of the leaf looks the same. this shows that carbon dioxide is required for photosynthesis
• indicator for carbon dioxide under water: sodium hydrocarbonate
• sodium hydrocarbonate are a source of carbon dioxide in the water
• carbon dioxide concentration is changed by changing the percentage of sodium hydrocarbonate is in the water
• as the concentration of carbon dioxide increase, more bubbles are formed
• after an optimum carbon dioxide concentration, the number of bubbles produced remain constant