Essay: Effect of commercial drinks (white wine, orange juice, and lemonade) on tooth enamel

Abstract:
In relation to the dentist’s letter, this report has been written to highlight the effect of some commercial drinks (white wine, orange juice, and lemonade) on tooth enamel and to decide the order of which is best for the patients. The trial used three drinks, as mentioned above, and by titrating them with sodium hydroxide (NaOH) solution, the results were obtained. In general, if a drink has a high pH, it will be less acidic. As a result, orange juice was noted as the highest pH (3.66) which makes it the most suitable drink for the patients compared to white wine (2.59) and lemonade (2.49). Therefore, orange juice should be recommended to the patients and lemonade should be avoided.
Introduction:
Titration is an analytical process in which the amount of some constituent of a sample is determined by adding to the measured sample a precisely known quantity of another substance with which the coveted constituent reacts in a definite, known proportion. This process is usually done by gradually adding a standard solution (i.e., a solution of known concentration) of titrating reagent, or titrant, from a burette, typically a long, graduated measuring tube with a stopcock and a delivery tube at its lower end. The addition is stopped when the endpoint is reached.
HA(aq)+OH-(aq)→H2O(l)+A-(aq)
(HA represents the acid, and A- is the conjugate base of HA).
The main aim of carrying out this experiment is to distinguish between the acidic drinks in terms of their pH levels. In order to choose the most suitable one out of the three drinks (white wine, lemonade and orange juice), the strength and concentration of the acidic drinks need to be evaluated by titrating them with a solution of NaOH. The more acidity a drink is, the more harmful on the patients’ teeth, as acidity content has an erosive potential on teeth enamel (Livestrong, 2017).
Safety assessment:
Risk
Safety
NaOH
(0.1066M)
Harmful to eyes
-Rinse with water for about 15 minutes
– Wear suitable eye and face protection
Can cause severe skin burns
-Rinse thoroughly with water. Seek medical attention if needed
-Wear protective gloves
If swallowed
Wash your mouth
Spillage
-Wipe the surface clean and dispose it off properly.
Phenolphthalein indicator (C20H14O4)
Can possibly cause eye irritation
-Wash with water for a minimum of 15 minutes. Get medical aid if needed.
-Wear chemical splash goggles.
Can possibly cause skin irritation especially in case of absorption
-Wash the skin with plenty of water.
-Wear suitable protective gloves and clothes to minimise skin exposure
Can possibly cause respiratory tract if inhaled.
Go directly to a place that has fresh air
Materials:
• Beakers (3×100 mL) [each drink];
• Burette (50 mL);
• Pipette (25 mL);
• Conical flasks (3×250 mL) [each drink];
• Phenolphthalein indicator;
• NaOH (standardised concentration);
• Acidic drinks (Orange juice, lemonade, white wine);
• Stand;
• pH meter.
Procedure:
25 mL of each drink was pipetted out, with making sure that there were no bubbles. Then, each drink was put in a separate beaker (100 mL), before two drops of Phenolphthalein indicator were added to the drinks in the conical flasks (250 mL). After placing the burette in the ring stand, it was filled with NaOH and the initial reading was recorded. Next, the burette valve was opened and the titrant ran out steadily (drop by drop) of the burette into the conical flask. The flask was gently swirled till it reached the endpoint at which it was indicated by a colour change. The valve was closed and the final reading was noticed and written down as the titration process was completed. Finally, steps were repeated two more times till three titres were obtained. Same procedure was repeated using different drinks.
-NaOH was standardised by KHP (mentioned in the appendix in details)
Data:
Table 1: pH values measured using a pH meter
The table below demonstrates pH values of the drinks, which were measured by PH meter using the correlation between PH and concentration.
[H+] =10-PH
Acidic drinks
Lemonade
White wine
Orange juice
PH value
2.49
2.59
3.66
Table 2: pH values measured using titration
The table below lists the results recorded from titration
Acidic drinks
Trials
Initial volume(mL)
Final volume(mL)
pH meter value
Volume of NaOH used(L)*
Change in colour
Lemonade
1
13.1
2.49
0.0131
Light pink
2
13.3
0.0133
3
13.6
0.0136
White wine
1
18
2.59
0.0180
Light brown
2
17.8
0.0178
3
17.9
0.0179
Orange juice
1
28.9
3.66
0.0289
Dark orange
2
28.8
0.0288
3
29
0.0290
Calculations:
*- Volume of NaOH used (L) =
– Molarity of NaOH =0.1202 M
– Molarity of NaOH volume of NaOH = molarity of drink volume of drink.
– Molarity of the drink=
-pH=-log[H+]
The above equation was used to calculate the molarity (concentration) of each drink as the concentration of NaOH was already obtained using standardisation method and the volume of both NaOH and each drink were measured. Molarities of the three drinks were used in the correlation between pH and H+ to acquire the pH values.
Lemonade
Average volume of NaOH used (L) ==0.0133L
Molarity of lemonade ==0.0639 M
pH=-log [Molarity of lemonade] =-log(0.0639)= 1.19
Drink
Molarity (M)
pH value
Lemonade
0.0639
1.19
White wine
Average volume of NaOH used (L) =0.0179L
Drink
Molarity (M)
pH value
White wine
0.0861
1.07
Orange juice
Average volume of NaOH used (L) =0.0289L
Drink
Molarity (M)
pH value
Orange juice
0.139
0.86
Discussion:
It was assumed that all the drinks were strong monoprotic acids that dissociate completely. However, the experiment showed that these drink only partly dissociated which means that they are weak acids. Each drink contains different type of acids. For instance, citric acid can be found in orange juice, food-grade organic acid can be found in lemonade and malic and tartaric acids can be found in white wine (Livestrong, 2017). As it is demonstrated in the table below, the pH values of the three drinks differed depending on the method used to calculate it (titration or pH meter) because of the wrong assumption that was made.
Table 4:
pH value
Lemonade
White wine
Orange juice
pH meter
2.49
2.59
3.66
Titration
1.19
1.07
0.86
It can be clearly observed that lemonade has the lowest pH value (2.49), whereas white wine has a pH value of 2.59. In contrast with these drinks, the highest pH value and the lowest acidity content can be found in orange juice which means that orange juice (pH=3.66) is relatively the least erosive to the tooth enamel.
Evaluation:
The values of pH that were measured by a pH meter were more accurate than the titration values due to human errors. For example, the possible existence of air(bubbles) in the burette, which can impede the flow of the added solution, might have led to inaccurate results. Moreover, the drinks were pipetted into a beaker, then the indicator was added and then poured into the conical flask which might have led to some remains being leftover and not fully transferred into the conical flask. Furthermore, the pipette was washed and might not have dried utterly which might have contributed to the analyte being slightly diluted. To acquire better results, the burette should have been emptied of air and the burette should have been dried before using it.
Conclusion:
In conclusion, orange juice is the best acidic drink owing to its low acidity content, while lemonade is the most harmful one to tooth enamel. Consequently, patients must be recommended to limit their consumption of these drinks especially lemonade, which has the greatest effect between the three drinks and then White wine and orange juice respectively.
List of references:
1. Acros.com. (2007). MATERIAL SAFETY DATA SHEET Phenolphthalein. [online] Available at: https://www.ch.ntu.edu.tw/~genchem99/msds/exp14/phenolphthalein.pdf [Accessed 30 Mar. 2018].
2. acros.com. (2014). MATERIAL SAFETY DATA SHEET Potassium hydrogen phthalate. [online] Available at: https://www.ch.ntu.edu.tw/~genchem99/msds/exp15/ KHP.pdf [Accessed 30 Mar. 2018].
3. Encyclopedia Britannica. (n.d.). Titration | chemical process. [online] Available at: https://www.britannica.com/science/titration [Accessed 15 Apr. 2018].
4.  LIVESTRONG.COM. (2017). The Types of Acidic Juices. [online] Available at: https://www.livestrong.com/article/307666-the-types-of-acidic-juices/ [Accessed 15 Apr. 2018].
Appendix:
Title: standardisation of a solution of sodium hydroxide with potassium hydrogen phthalate.
Introduction:
Standardisation is a process of ascertaining the accurate concentration (molarity) of a solution. The methodical procedure often used for this purpose called titration. When titrating sodium hydroxide (NaOH) with potassium hydrogen phthalate (KHP), an exact volume of NaOH is reacted with a known amount of KHP. The point at which a titration reaction is complete is known as the endpoint. The point is indicated by a colour change caused by an indicator (here phenolphthalein).
The purpose of conducting this experiment is to standardise an unknown concentration of a solution of NaOH by titration with a known concentration of KHP.
This reaction happens as presented in the following equation:
KHC8H4O4 (aq) + NaOH (aq) NaKC8H4O4 (aq) +H2O(l)
Safety assessment:
Risks
Safety
NaOH
(0.1066M)
Harmful to eyes
-Rinse with water for about 15 minutes.
-Wear eye and face protection
Can cause severe skin burns
-Rinse thoroughly with water/ Seek medical attention if needed.
-Wear protective gloves to prevent skin contact.
If swallowed
Wash your mouth
Spillage
Wipe the surface clean and dispose it off properly.
Phenolphthalein indicator
Can possibly cause eye irritation
-Wash with water for a minimum of 15 minutes. Get medical aid if needed.
-Wear chemical splash goggles.
Can possibly cause skin irritation especially in case of absorption
-Wash the skin with plenty of water.
-Wear suitable protective gloves and clothes to minimise skin exposure
Can possibly cause respiratory tract if inhaled.
Go directly to a place that has fresh air
KHP(C8H5KO4)
Irritant to eyes
-Rinse eyes with water for at least 15 minutes.
-Wear suitable protective chemical safety goggles
Irritant to skin
-Wash skin with water directly
-See a doctor if needed
-Wear suitable protective gloves and clothes to minimise skin exposure
Irritant to digestive tracts
-Do not try to vomit
-Ask for medical help
Materials:
• Beakers (3×100 mL);
• Conical flasks (3×250 mL);
• Squirt bottle [Distilled water 125 mL];
• Potassium hydrogen phthalate(KHP);
• Phenolphthalein indicator:
• Sodium hydroxide (NaOH);
• Burette (50 mL);
• Analytical balance;
• clamp;
• Spatula;
• Valve;
• Weighing boat;
• White tile.
Method:
Initially, the TARE button was pressed after a clean weighing boat was placed on an analytical balance. After that, between 0.6g and 0.7g of KHP was transferred into the weighting boat (while on the balance) using a spatula. Then, the measured weight of KHP was transferred into a beaker (100 mL) and 20mL of water was added and swirled until the KHP dissolved and then transferred into a conical flask (250 mL). Following that, 1-2 drops of Phenolphthalein were added to the conical flask ready to be placed under the burette. Next, the burette was filled with NaOH and the initial reading was noted. Burette valve was opened and NaOH was dripping into the conical flask. Afterwards, the flask was swirled gently until the light pink colour was seen, which means that the solution reached its endpoint. Finally, the final reading was noted.
Calculations:
-Moles of KHP =
-Molar mass of KHP =(8×12.01)+(5×1.008)+(39.10)+(4×16.00)=204.22 g/mol
-Moles of NaOH = Moles of KHP
-Molarity of NaOH (mol.L-1) =
1st trial
2nd trial
3rd trial
Mass of KHP(g)
0.6256
0.6034
0.6149
Initial burette reading(ml)
50
50
50
Final burette reading(ml)
25.8
24
25
Volume of NaOH used (mL)
24.2
26
25
Volume of NaOH used (L)
0.0242
0.026
0.025
Moles of KHP(mol)
3.063×10-3
2.955×10-3
3.011×10-3
Moles of NaOH(mol)
3.063X10-3
2.955×10-3
3.011×10-3
Molarity of NaOH (M)
0.1266
0.1137
0.1204
-Average molarity of NaOH = =0.1202
-Accepted molarity of NAOH =0.1066M
-Percent error = x100
=x100=12.76%
Discussion:
The chemical reaction can be illustrated in the following equations:
-KHC8H4O4 (aq) + NaOH (aq) KN4C8H4O4 (aq) + H2O(l)
-HC8H4O4 – +OH – C8H4O4 -2 + H2O.
It can be obviously noticed that the percent error is quite high. This can be due to the inaccuracy in time when the colour changed the final point was taken while the solution might not have been completely mixed. Furthermore, it is possible that the amount of KHP was not fully dissociated in water.
Conclusion:
To conclude, the precise concentration of NaOH (0.1202M) was known by titration with the help of KHP as a primary standard. Therefore, NaOH molarity value is recommended for similar titration experiments to estimate acidity contents.