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Acid-Base Titration: Standardizing HCl with 0.1M NaOH

Experiment video

What you will learn

Determine the strength and molarity of a given Hydrochloric Acid (HCl) solution by titrating against a standard 0.1 M Sodium Hydroxide (NaOH) solution using phenolphthalein indicator.

Materials needed

Standard 0.1 M NaOH Solution mL
Standard 0.1 M NaOH Solution mL
₹50
What is it?
Class A precision 50 mL glass burette with straight bore PTFE stopcock and 0.1 mL graduations.
Specifications
Capacity
50.0 mL
Tolerance
± 0.05 mL (Class A)
Stopcock
Self-lubricating PTFE stopcock
Material
Borosilicate glass 3.3
Unknown HCl Solution mL
Unknown HCl Solution mL
₹95
What is it?
Standardized 0.100 M Sodium Hydroxide secondary standard solution prepared in carbon dioxide free water.
Specifications
Concentration
0.100 M (0.100 N)
Purity
AR Analytical Reagent grade
Standardization
Calibrated against primary standard potassium hydrogen phthalate
Bottle
Airtight amber HDPE container
Phenolphthalein Indicator Solution dropper bottle
Phenolphthalein Indicator Solution dropper bottle
₹140
What is it?
Volumetric one-mark bulb pipette calibrated to deliver (TD) at 20°C.
Specifications
Volume
20.00 mL
Tolerance
± 0.03 mL (Class A)
Marking
Amber permanent enamel index
Flow Time
25 – 30 seconds standard delivery
Burette (50 mL, 0.1 mL graduation) with clamp stand
Burette (50 mL, 0.1 mL graduation) with clamp stand
₹185
What is it?
0.1% Phenolphthalein indicator solution in 95% ethyl alcohol.
Specifications
pH Range
8.2 (colorless) to 10.0 (magenta/pink)
Solvent
50% ethanol / 50% distilled water
Dispenser
Amber dropper bottle with glass pipette
Volumetric Pipette (20 mL or 25 mL) with safety bulb
Volumetric Pipette (20 mL or 25 mL) with safety bulb
₹230
What is it?
Standard laboratory apparatus used in Acid-Base Titration: Standardizing HCl with 0.1M NaOH.
Specifications
Category
Chemistry Apparatus
Grade
CBSE / NEP 2020 Laboratory Standard
Conical Flasks (250 mL)
Conical Flasks (250 mL)
₹275
What is it?
Standard laboratory apparatus used in Acid-Base Titration: Standardizing HCl with 0.1M NaOH.
Specifications
Category
Chemistry Apparatus
Grade
CBSE / NEP 2020 Laboratory Standard
Glass Funnel, Wash Bottle with Distilled Water set
Glass Funnel, Wash Bottle with Distilled Water set
₹320
What is it?
Standard laboratory apparatus used in Acid-Base Titration: Standardizing HCl with 0.1M NaOH.
Specifications
Category
Chemistry Apparatus
Grade
CBSE / NEP 2020 Laboratory Standard
White porcelain tile
White porcelain tile
₹365
What is it?
Standard laboratory apparatus used in Acid-Base Titration: Standardizing HCl with 0.1M NaOH.
Specifications
Category
Chemistry Apparatus
Grade
CBSE / NEP 2020 Laboratory Standard

Tick items as you collect them. Tap + to see the product, specifications and buy options.

Stay safe

Always remove the glass funnel from the top of the burette before taking readings to avoid dripping.
Ensure no trapped air bubble remains in the burette stopcock nozzle.
Do not blow out the last drop remaining in the pipette tip; it is calibrated for retention.
Use only 2-3 drops of indicator; excessive indicator consumes titrant and skews the endpoint.

Steps

0 of 7 steps done

1Rinse and fill the burette with standard 0.1 M NaOH solution, ensuring no air bubbles in the jet.
Observation
Rinse burette with distilled water, then with standard 0.1 M NaOH solution; ensure jet tip is filled with no air bubbles.
Safety
Clamp burette vertically; wear safety splash goggles and nitrile gloves.
2Adjust the NaOH meniscus to exactly 0.0 mL with the bottom of the curve touching the mark.
Observation
Adjust meniscus to exactly 0.00 mL with lower curve of clear NaOH solution resting precisely on zero mark.
Safety
Remove plastic funnel from top of burette before taking initial reading to prevent titrant droplets.
3Rinse a 20 mL pipette with the unknown HCl solution and pipette exactly 20.0 mL into a clean conical flask.
Observation
Pipette exactly 20.00 mL of unknown HCl into clean 250 mL conical flask; touch pipette tip to inner wall.
Safety
Never pipette acids by mouth; always use a rubber pipette suction bulb.
4Add 2 to 3 drops of phenolphthalein indicator into the flask (solution remains colorless in acidic medium).
Observation
Add 2 drops of phenolphthalein indicator; swirling shows solution remains completely clear and colorless.
Safety
Do not add excessive indicator (max 2-3 drops) as indicators are weak acids.
5Place the flask on the white tile below the burette tip to observe sharp color transitions.
Observation
Titrate with steady swirling over white tile until a single drop produces permanent faint pink tint lasting 30 s.
Safety
Control stopcock with left hand around barrel; swirl flask with right hand.
6Add NaOH dropwise while swirling constantly until a single drop imparts a permanent pale pink tint.
Observation
Final reading 19.60 mL; concordant trials confirm exact HCl molarity = 0.0980 M.
Safety
Neutralize and rinse waste solutions down the sink with excess tap water.
7Record the final burette reading. Repeat the titration until three concordant burette readings (±0.05 mL) are obtained.

Tap + on a step to see what you will observe and any safety tips.

Record your observations

Burette Trial	Initial Burette (mL)	Final Burette (mL)	Volume NaOH Used (mL)	Concordance Status
Rough Pilot	0.00 mL	20.10 mL	20.10 mL	Pilot estimate
Trial 1	0.00 mL	19.65 mL	19.65 mL	Recorded
Trial 2	19.65 mL	39.25 mL	19.60 mL	Concordant
Trial 3	0.00 mL	19.60 mL	19.60 mL	Concordant (V = 19.60 mL)
Trial 4	19.60 mL	39.20 mL	19.60 mL	Concordant confirmed

Tap a highlighted cell to write your own observation.

Result and conclusion

Equivalence point reached when solution turns faintly pink lasting 30 seconds. Concordant burette readings determine the exact concentration of HCl as 0.098 M.

M(HCl) · V(HCl) = M(NaOH) · V(NaOH) => M(HCl) = (0.100 M × 19.60 mL) / 20.00 mL = 0.0980 M

Observation	What it means
Sharp Equivalence Point	A single drop (0.05 mL) of 0.1M NaOH turns the solution from clear to persistent faint pink lasting > 30 seconds.
Concordant Burette Volume	Three consecutive trials yield identical 19.60 mL titrant volume (±0.05 mL tolerance).
Precise Molarity Determination	Calculated molarity of hydrochloric acid is exactly 0.0980 M (strength = 0.0980 × 36.5 = 3.577 g/L).
Indicator Suitability	Phenolphthalein pH transition interval (8.2 – 10.0) coincides perfectly with the steep equivalence surge of a strong acid - strong base titration.

Strong Acid - Strong Base Titration pH Curve

Sample readings. Replace with your own results.

Experiment photos

Before the experimentDuring the experimentResult