1. MOST COST-EFFECTIVE BRAND OF BAKING SODA Keerthana Sundar, Deepa Selveraj, Desiree Chew and Amanda Lee from 211

2. Contents Introduction Research Questions Hypothesis Background Information Methodology Results Data Analysis Conclusion Reflections Limitations/Possible Extensions of project

3. Introduction The purpose of this Research Studies project is to find out the most cost- effective brand of baking soda. This knowledge we acquire will be helpful to professional bakers and others who frequently use baking soda so that they can buy the most effective baking soda with the least amount of money.

4. Introduction This project will also educate people on the science behind baking soda.

5. Research Questions Which brand of baking soda is the most cost-effective? How do you determine the most cost- effective baking soda? What are the differences between baking powder and baking soda? How does baking soda work?

6. Hypothesis The greater the concentration of sodium bicarbonate in the baking soda, the more effective it is, for smaller amount of baking soda is needed for the same purpose. The greater the volume ratio of sodium bicarbonate per dollar, the more cost-effective it is.

7. Background Information – what is baking soda? Sodium bicarbonate (NaHCO 3 ) NaHCO 3 reacts with HCl (hydrochloric acid) acid to form sodium, water and carbon dioxide, as shown in the equation below. NaHCO 3 + HCl -----> NaCl + H 2 0 + CO 2 (soda) (acid) (sodium) (water) (gas) Our experiment simulates the chemical reaction which baking soda undergoes during baking.

8. Background information – what is baking soda? Recipes that use baking soda for leavening always have an acidic ingredient. Some interesting uses of Baking Soda : - Cleaning Agent (Cleans toilets, Marble, Dried food on pans…) - Deodorizes Fridge and Freezer - Medical (relieve general skin irritations such as measles and chicken pox. Apply baking soda directly to insect bites, rashes and poison ivy to relieve discomfort. ) - When scalding a chicken, add 1-teaspoon of baking soda to the boiling water. The feathers will come off easier and flesh will be clean and white.

9. Difference between baking soda and powder Baking SodaBaking Powder IngredientsSodium Bicarbonatecombination of baking soda and a few other ingredients, and most importantly a dry acid Type-1) Double-acting - The first "action" occurs when baking powder is wet -The second "action" occurs when baking powder is heated 2) Single-acting Required for reaction to occur AcidWet ingredients (dry acid and baking soda will react)

10. Materials and Apparatus ApparatusQuantityRemarks Retort Stand1 Electronic Balance1 Burette1 Baking soda1 bottle Screened Methyl Orange1 bottle Distilled water1 bottle Conical Flask1 Funnel2 White Tile1 Beakers2 Hydrochloric acid (HCl)40cm 3 0.2mol/dm -3 Sodium hydroxide (NaOH)50cm 3 0.2mol/dm -3

11. Materials: Brands that we used Arm and Hammer Bake King - $1.15 per 100g Red Man - $1.00 per 50g

12. Methodology (STEP BY STEP) 1.Accurately measure 0.2g of baking soda on the electronic balance and put into the conical flask. 2.Titrate 40cm 3 of HCl into the 0.2g of baking soda. 3.Add 3 drops of Screened Methyl Orange to the conical flask, the liquid will turn purple, indicating the excess of acid in the conical flask. 4.Back titrate with the NaOH until the liquid turns green, indicating the neutralisation. 5.Record the amount of NaOH that has been displaced into the conical flask. 6.From this, calculate the amounf o acid that has neutralised with 0.2g of baking soda.

13. Methodology - Process of titration (using Bake King baking soda) Bake King + hydrochloric acid, before being titrated. Pinkish colour is due to the addition of screened methyl orange. The colour shows that the content of the Erlenmeyer flask is acidic. After titration, the screened methyl orange indicator turns green. This signifies that the solution has reached the ending point of titration.

14. Methodology – back titration Keerthana and Amanda titrating the Arm and Hammer brand baking soda. After the ending point, when we are going to record our results, it is important to read at the bottom of the meniscus in the burette.

15. Methodology – methods we considered Other methods we considered: - Adding acid to baking soda and measuring the amount of Carbon Dioxide released by gravimetric analysis IS IT BY GRAVIMETRIC ANALYSIS? OR BY PUTTING IT INTO THE CO2 CHAMBER? - Titration An appropriate method is to use is back titration: - gives us the exact readings of up to 0.1 cm 3 that are extremely accurate as a burette is used. - measure the change in colour, which is easier than measuring when the fizzing stopped

16. Methodology – our various trials We experimented with 2g and 1g of baking soda at first but realised that it was too much for the 40cm 3 of HCl to even neutralise. Hence, we decided to experiment with a smaller amount of baking soda: 0.2g and added in 40cm 3 of HCl such that there was excess unreacted acid left.

17. Methodology – data collection The smaller the volume the alkaline needed to react with excess HCl, the more cost effective the baking soda This is because, when less alkaline is needed to neutralise with the excess acid, more acid has neutralised with the Sodium BiCarbonate, indicating a higher level of Sodium BiCarbonate in the Baking Soda Higher amount of acid larger concentration of NaCO3 the more effective the baking soda Reacted HCl – amount of NaCO 3 in baking soda Excess unreacted HCl Alkaline needed to react with excess HCl

18. Results

19. Data Analysis The greater the volume ratio, the smaller the amount of baking soda needs to be used in baking. This gives rise to a prolonged use of baking soda. Thus, the one with the greater volume ratio of NaHCO3 is the most cost-effective.

20. Conclusion

21. Challenges we faced Baking powder could not be used for this experiment because baking powder already contains acid. Titration could not be used for baking soda; therefore we used back titration. For baking soda, could not determine when the chemical reaction had stopped by simply looking at the fizzing Found more brands of baking powder than soda

22. Contd Time constraints – RS sessions with mentor was disrupted due to school events. Learning how to titrate the correct way. (lasted for 3 sessions) We were unsure of how to interpret the results of our experiment – Back titration is different from titration. We could only find 3 commercially available brands in Singapore. Due to monetary constraints, we could not get more brands from the US.

23. Reflections of the project What we feel we have done well… Working well as a team Working with tight deadlines, such as coming up with the proposal, doing the experiment and getting results within a few sessions. What we feel we need to improve on… Should have tackled the issue from different angles, we could have used more methods to validate our results. Limitations of the project… That we dont have apparatus to make our own cost- effective brand of baking soda.

24. Extension of project Repeat this experiment more times, to get even more accurate data, with less errors. We would like experiment and find out how we can ascertain the most cost-effective brand of baking powder. Titration may not be the best method to do so – we realised – because baking powder already contains acid. Using the results we have gathered and apply it to baking real goods and see if our results hold true. Share our results with those who can benefit from this and teach them how baking soda works.