NAME: HIEP TON
November 21, 2014
LAB 6 ACID-BASE TITRATION OF VINEGAR
I.
OBJECTIVE :
• Determine the Concentration (Molarity) of Acid – Base.
II.
DATA and REPORT :
1. PREPARATION OF 0.1M SODIUM HYDROXIDE SOLUTION
Volume of NaOH and water added: 0.0102 L
2. PREPARATION OF KHP and STANDARDIZATION OF SODIUM HYDROXIDE SOLUTION
A. Preparation of KHP standard Solution (0.1 M) in 25 ml Volumetric flask
Mass of KHP taken
Volume of solution (KHP solid and Water)
Molar Mass of KHP
0.5372 g
0.0250 L
204.22 g/mol
1𝑚𝑜𝑙𝑒
Mole of KHP: 0.5372 g × 204.22g = 2.6305 x 10−03 moles
Concentration of KHP:
2.6305 x 10−03 moles
0.0250 L
≈ 0.1052 𝑀
B. Standardization of 0.1 M NaOH solution
Equation: 1 KHP (aq) + 1 NaOH (aq) → 1 Salt (s) + 1 H2O (l)
Using Trial 1 to show the calculation:
Formula: MKHP VKHP = MNaOH VNaOH
→ 0.1052 𝑀 × 1.1 𝐿 = 𝑀𝑁𝑎𝑂𝐻 × 1.4 𝐿
→ 𝑀𝑁𝑎𝑂𝐻 =
0.1052 𝑀 × 1.1 𝐿
1.4 𝐿
= 0.0827 𝑀
Page 1 of 3
NAME: HIEP TON
November 21, 2014
Table 1: KHP and NaOH
Initial Volume of KHP (mL)
Final Volume of KHP (mL)
Volume of KHP taken (mL)
Final Volume of NaOH (mL)
Final Volume of NaOH (mL)
Volume of NaOH used (mL)
Concentration of NaOH
Trial 1
0.0
1.1
1.1
Trial 2
0.0
1.0
1.0
Trial 3
0.0
1.0
1.0
0.0
1.4
1.4
0.0
1.3
1.3
0.0
1.3
1.3
0.0827 M
0.0809 M
0.0809 M
The Average Concentration of NaOH from 3 trials:
→ 𝑀𝑁𝑎𝑂𝐻 =
0.0827 𝑀 + 0.0809 𝑀 + 0.0809𝑀
= 0.0815 𝑀
3
3. TITRATION ACETIC ACID (vinegar) USING SODIUM HYDROXIDE SOLUTION
Equation: 1 CH3COOH (aq) + 1 NaOH (aq) → 1 Salt (s) + 1 H2O (l)
Note:
 MAA is the Concentration of Acetic Acid
 VAA is the Volume of Acetic Acid
 Average Concentration of NaOH: 0.0815 M (calculated above)
 Molar Mass of Acetic Acid (provided): 60.05 g/mol
 Number of Sample Brand: 3
Using Trial 1 to show the calculation:
Formula: MAA VAA = MNaOH VNaOH
→ 𝑀𝐴𝐴 × 0.00025 𝐿 = 0.0815 𝑀𝑁𝑎𝑂𝐻 × 0.0024 𝐿
→ 𝑀𝐴𝐴 =
0.0815 𝑀𝑁𝑎𝑂𝐻 × 0.0024 𝐿
0.00025 𝐿
= 0.7824 𝑀
Page 2 of 3
NAME: HIEP TON
November 21, 2014
Table 2: Acetic Acid and NaOH
Initial Volume of Acetic Acid (mL)
Final Volume of Acetic Acid (mL)
Volume of Acetic Acid taken (mL)
Final Volume of NaOH (mL)
Final Volume of NaOH (mL)
Volume of NaOH used (mL)
Concentration of Acetic Acid
Trial 1
0.0
0.25
0.25
Trial 2
0.25
0.51
0.26
0.0
2.40
2.40
0.0
2.50
2.50
0.7824 M
0.7837 M
The Average Concentration of Acetic Acid from 2 trials:
→ 𝑀𝐴𝐴 =
III.
0.7824 𝑀 + 0.7837 𝑀
= 0.7831 𝑀
2
DISCUSSION :
 It was hard to measure exactly the amount of NaOH wanted because could not
cut/divide the drop into smaller amount.
 Even though the endpoint could be determined by the color observed by ordinary eyes,
it was difficult and surely contained a certain amount of error since the possibility of
reaching the exact correct endpoint is very extremely low.
 Therefore, without using any measurement equipment to evaluate the Concentration,
there are always some percentages of error in the calculation deal to the uncertainty of
data collected.
IV.
CONCLUSION:
 Being able to determine the Concentration of Acid-Base is important. For instance, by using the
technics, the brand of vinegar can be bought with great consideration.
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