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Chemistry Lab Report

🔬 Significance of Chemistry

Chemistry plays a crucial role in our daily lives and in solving global challenges. It is the central science that connects physics, biology, and environmental science, enabling progress across multiple fields.

Health and Medicine: Development of life-saving drugs, vaccines, and diagnostic tools.
Environment: Pollution control, water purification, and sustainable energy solutions.
Agriculture: Fertilizers, pesticides, and soil testing for better crop yields.
Materials: Creation of plastics, ceramics, metals, and nanomaterials used in everyday products.
Food: Preservatives, flavorings, and nutritional content analysis for safer, better food.
Clean Energy: Development of batteries, solar panels, and fuel cells for a sustainable future.

In essence: Chemistry helps us understand the world at a molecular level and empowers innovation that benefits society, the economy, and the planet.

"If you can't fly then run,if you can't run then walk,if you can't walk then crawl,but whatever you do you have to keep moving forward." ~ Martin Luther King Jr.

Welcome to the Chemistry Lab

This portal contains experiment details, diagrams, observations, and results for various chemistry practicals.

Significance of a Chemistry Laboratory

Hands-on Learning

The lab brings theoretical concepts to life. Students get to see chemical reactions, handle apparatus, and understand principles better through direct experience.

Skill Development

Working in the lab builds essential scientific skills like precise measurement, observation, analytical thinking, and safety awareness.

Innovation and Discovery

Labs are the birthplace of new compounds, materials, and ideas. Many life-saving drugs and technological advances started in a chemistry lab.

Understanding Safety and Ethics

Practicing lab safety and ethical handling of chemicals is vital for real-world scientific work.

Critical Thinking and Problem Solving

Experiments often have unexpected results. Interpreting them teaches students how to think critically and troubleshoot effectively.

Collaboration and Communication

Labs often involve teamwork, encouraging collaboration and clear communication—skills needed in any scientific or technical career.

Essential Chemistry Lab Safety Rules

Wear Proper Lab Attire

Lab coat, safety goggles, gloves, and closed-toe shoes are a must. Tie back long hair.

No Eating or Drinking

Never bring food or drinks into the lab. Chemicals and snacks don’t mix!

Handle Chemicals Carefully

Read labels twice. Never taste or directly smell chemicals—waft instead.

Use Flames Safely

Keep flammable materials away from open flames. Know how to use a fire extinguisher.

Keep Your Area Clean

Tidy workspace = safer workspace. Clean spills immediately and dispose of waste properly.

Follow Instructions

Always follow your teacher’s or lab manual’s instructions. Don’t improvise.

Know Emergency Procedures

Know the location of safety showers, eyewash stations, fire extinguishers, and first aid kits.

Report Accidents

Tell your teacher about spills, broken glass, or any injuries right away—big or small.

Label and Store Properly

Label all containers clearly and store chemicals as instructed.

Wash Hands After Experiments

Always wash up before leaving the lab—even if you wore gloves.

List of Chemicals and Hazards

Chemical Name	Hazards
Hydrochloric Acid (HCl)	Corrosive, causes burns, harmful if inhaled
Sodium Hydroxide (NaOH)	Highly corrosive, causes severe burns, reacts with water
Sulfuric Acid (H₂SO₄)	Corrosive, causes burns, reacts violently with water
Acetone	Flammable, irritant, causes dizziness if inhaled
Benzene	Carcinogenic, flammable, harmful via inhalation or skin
Ammonia (NH₃)	Toxic if inhaled, corrosive to eyes/skin, strong irritant
Ethanol (C₂H₅OH)	Flammable, irritant, depressant of nervous system
Nitric Acid (HNO₃)	Strong oxidizer, corrosive, toxic fumes
Chloroform (CHCl₃)	Possible carcinogen, liver/kidney harm, narcotic effect
Mercury (Hg)	Toxic by inhalation, harmful to nervous system
Phenol	Toxic, corrosive, can cause systemic poisoning via skin
Hydrogen Peroxide (H₂O₂)	Oxidizer, may explode under pressure, causes burns
Potassium Cyanide (KCN)	Extremely toxic, fatal if ingested or inhaled

12 Principles of Green Chemistry

Prevention

Better to prevent waste than to treat or clean it up after it’s formed.

Atom Economy

Maximize incorporation of materials into the final product.

Less Hazardous Chemical Syntheses

Use and generate substances with little or no toxicity.

Designing Safer Chemicals

Design products that are effective and have minimal toxicity.

Safer Solvents and Auxiliaries

Use safer auxiliary substances only when necessary.

Design for Energy Efficiency

Minimize energy usage and favor ambient temperature/pressure.

Use of Renewable Feedstocks

Prefer renewable raw materials over depleting ones.

Reduce Derivatives

Avoid unnecessary derivatization steps.

Catalysis

Use catalytic reagents over stoichiometric ones.

Design for Degradation

Chemical products should break down into harmless substances.

Real-time Analysis for Pollution Prevention

Enable monitoring control to prevent hazardous substances.

Inherently Safer Chemistry for Accident Prevention

Use safer substances to reduce risks.

Laboratory Record Format

Experiment Details
Experiment Title:	___________________________________________
Aim:	___________________________________________
Apparatus and Chemicals:	___________________________________________
Theory:	___________________________________________
Procedure:	___________________________________________
Observations:	___________________________________________
Calculations:	___________________________________________
Result:	___________________________________________
Precautions:	___________________________________________

Apparatus

Burette

A burette is a long, graduated glass tube with a tap at the bottom, used in chemistry labs to accurately deliver measured volumes of liquid, especially during titrations. It allows for precise control of the liquid flow, helping determine the exact amount of a solution needed to react with another substance.

Conical Flask

A conical flask, also known as an Erlenmeyer flask, is a glass container with a wide base that tapers to a narrow neck. It is commonly used in labs for mixing, heating, and storing liquids. The narrow neck helps prevent spills and reduces evaporation, making it ideal for titrations and reactions that need swirling without losing contents.

Beaker

A beaker is a simple, cylindrical glass container with a flat bottom and a small spout for pouring. It’s commonly used in laboratories for mixing, stirring, heating, and measuring liquids (though not very precisely). Beakers come in various sizes and are often marked with volume graduations for rough measurements.

Measurement Tube

A measurement tube in chemistry typically refers to a graduated cylinder or measuring tube used for accurately measuring liquid volumes in experiments.

Experiment 1: EDTA Complexometric Titration

Formula of M-EDTA

Formula of EDTA

Titration process

1. Flow chart

Take 10 ml water sample
Add Buffer Solution (pH ~10) – 3 ml
Add Eriochrome Black T (EBT) – 2–3 drops
Titrate with 0.01 M EDTA solution

2. Before Titration

Add 10 ml of water + 3 ml of buffer solution (pH ~10) + 2–3 drops of EBT indicator.
Solution turns wine red indicating presence of Ca²⁺ and Mg²⁺ ions forming a weak complex with EBT

3. During Titration

Titrate with 0.01 M EDTA solution.
EDTA binds with Ca²⁺ and Mg²⁺ ions to form a stable colorless complex.
As EDTA removes hardness ions, the wine red color fades.

4. End Of Titration

All hardness ions (Ca²⁺ and Mg²⁺) are complexed with EDTA.
EBT is free in solution and shows its original color.
Color changes from wine red to pure blue – indicates endpoint.

Aim

Determination of total hardness by complexometric titration method

Chemicals Used

0.1 M EDTA
Eriochrome Black T
Water sample
Buffer solution

Theory: Determination of Hardness by Complexometric Titration

Hardness of water is mainly caused by the presence of calcium (Ca²⁺) and magnesium (Mg²⁺) ions. In complexometric titration, these metal ions are quantitatively estimated using EDTA (Ethylenediaminetetraacetic acid), a chelating agent that forms stable, colorless complexes with them.

Key Steps :

A buffer solution (pH ~10) is added to maintain the pH level suitable for the reaction.
An indicator, Eriochrome Black T (EBT), is used. It forms a wine-red complex with Ca²⁺ and Mg²⁺.
As EDTA is added during titration, it binds with the metal ions, breaking the EBT-metal complex.
Once all metal ions are complexed by EDTA, the EBT is free and changes color from wine red to blue, indicating the endpoint.

Reactions

1. Ca²⁺/Mg²⁺ + EBT → [Ca/ Mg–EBT] (wine red)
2. [Ca/ Mg–EBT] + EDTA → [Ca–EDTA] + EBT (free, blue)

Observation Table

Trial	Initial Reading (mL)	Final Reading (mL)	EDTA Used (V₂ in mL)	Hardness (mg/L)
1	0.0	2.7	2.7	0.27
2	2.7	5.0	2.3	0.23
3	5.0	7.5	2.5	0.25
Average Hardness					0.25 mg/L

Formula Used

Hardness = (V₂ × C₂ × 100) / V₁

Calculations

Hardness = (V₂ × C₂ × 100) / V₁

= (0.25 × 100 x 10³ × 100) / 10

= 250 ppm

Result

The Hardness found in the water sample is 250 ppm

EDTA Complexometric Titration and Its Interaction with Sustainable Development

EDTA complexometric titration is a widely used method to determine metal ion concentrations, especially calcium and magnesium in water. Its interaction with sustainable development goals is important in several ways:

1. Monitoring Water Quality (SDG 6: Clean Water and Sanitation)

EDTA titration helps detect hardness in water (due to calcium and magnesium ions), which is crucial for ensuring safe drinking water and maintaining water treatment systems.
Regular water testing prevents water pollution and supports clean, accessible water for communities.

2. Environmental Protection (SDG 15: Life on Land & SDG 14: Life Below Water)

By monitoring heavy metals (like lead or mercury) in soil and water, EDTA titration helps in assessing pollution levels.
This protects ecosystems and promotes conservation of terrestrial and aquatic life.

3. Environmental Protection (SDG 15: Life on Land & SDG 14: Life Below Water)

Industries use EDTA titration to monitor metal waste and improve their waste treatment processes, reducing environmental impact and promoting greener practices.

4. Resource Management

By accurately measuring metal contents, industries can recycle materials more efficiently, minimizing waste and promoting a circular economy.

5. Challenges:

EDTA itself is not easily biodegradable and can contribute to environmental problems if not handled properly.
Therefore, green alternatives (like biodegradable chelators) are being researched to make complexometric methods even more sustainable.

Key Steps :

A buffer solution (pH ~10) is added to maintain the pH level suitable for the reaction.
An indicator, Eriochrome Black T (EBT), is used. It forms a wine-red complex with Ca²⁺ and Mg²⁺.
As EDTA is added during titration, it binds with the metal ions, breaking the EBT-metal complex.
Once all metal ions are complexed by EDTA, the EBT is free and changes color from wine red to blue, indicating the endpoint.

Reactions

1. Ca²⁺/Mg²⁺ + EBT → [Ca/ Mg–EBT] (wine red)
2. [Ca/ Mg–EBT] + EDTA → [Ca–EDTA] + EBT (free, blue)

Experiment 2: Alkalinity of Water

Method of Titration

Flow chart

10 mL water sample
0.01 N HCl (N/100)
Phenolphthalein (2–3 drops) Methyl Orange (2–3 drops)

Before Titration

Add 10 mL of water sample + 2–3 drops Phenolphthalein
If solution turns pink → presence of hydroxide or carbonate
No color → proceed to add Methyl Orange

During Titration

Titrate with N/100 HCl
Pink color disappears → record V₁ (Phenolphthalein alkalinity)
Add 2–3 drops of Methyl Orange
Continue titration → yellow to reddish color change
Record V₂ (additional volume for total alkalinity)

End Of Titration

All alkalinity neutralized
Final color: orange/pink

Aim

Determine the Alkalinity of given water samples.

Chemicals Used

Water sample, standard sulfuric acid (H₂SO₄) or hydrochloric acid (HCl), phenolphthalein indicator, methyl orange indicator, distilled water.

Determination of Alkalinity of Water using Phenolphthalein and Methyl Orange

Theory

Alkalinity of water refers to its capacity to neutralize acids and is primarily due to the presence of hydroxide (OH⁻), carbonate (CO₃²⁻), and bicarbonate (HCO₃⁻) ions. It plays a vital role in water chemistry as it affects the pH and buffering capacity of natural and treated waters. To determine alkalinity, we titrate the water sample using a standard acid solution (usually H₂SO₄ or HCl) with two indicators:

Phenolphthalein Indicator – changes from pink to colorless at pH ~8.3
Methyl Orange Indicator – changes from yellow to orange-red at pH ~4.5

Step 1: Titration with Phenolphthalein

This neutralizes OH⁻ and half of CO₃²⁻:

OH⁻ + H⁺ → H₂O
CO₃²⁻ + H⁺ → HCO₃⁻

The volume of acid used up to this point is noted as P (Phenolphthalein alkalinity).

Step 2: Titration with Methyl Orange

This neutralizes the remaining CO₃²⁻ (converted to HCO₃⁻ in step 1) and all the HCO₃⁻:

HCO₃⁻ + H⁺ → H₂CO₃

The total volume of acid used (from the start till methyl orange endpoint) is noted as T (Total alkalinity).

Chemical Reactions Involved

Hydroxide neutralization:OH⁻ + H⁺ → H₂O
Carbonate neutralization (in two stages):Stage 1 (phenolphthalein range): CO₃²⁻ + H⁺ → HCO₃⁻ Stage 2 (methyl orange range): HCO₃⁻ + H⁺ → H₂CO₃

🧪 Interpretation

By analyzing P and T, you can determine the type of alkalinity present:

Condition	Inference
P = 0	Only bicarbonate present
P = T	Only hydroxide present
P = ½T	Only carbonate present
P < ½T	Carbonate and bicarbonate
P > ½T	Hydroxide and carbonate

Observation Table (a) Using Phenolphthalein

S. No	Volume of solution taken in titration flask (ml)	Burette Reading Initial	Burette Reading Final	Volume of titrant used (ml)
1	10 ml	0.9	3.5	2.6
2	10 ml	2.7	5.4	2.7
3	10 ml	2.3	5.8	3.5
4	10 ml	3.5	6.2	2.7

Equivalent of phenolphthalein: 3.2 ml

(b) Using Methyl Orange

S. No	Volume of solution taken in titration flask (ml)	Burette Reading Initial	Burette Reading Final	Volume of titrant used (ml)
1	10 ml	4.9	9.6	4.7
2	10 ml	1.9	6.8	4.9
3	10 ml	1.9	6.8	4.9
4	10 ml	1.9	6.8	4.9

Equivalent by methyl orange: 5.8 ml

Calculation

(i) Phenolphthalein Indicator

N₁V₁ = N₂V₂
N₁ × 10 = 0.1 × 3.2
N₁ × 10 = 0.32
N₁ = 0.32 / 10
N₁ = 0.032 N

Alkalinity = 0.032 × 50 × 1000 mg/l
           = 1600 ppm

(ii) Methyl Orange

N₁V₁ = N₂V₂
N₁ × 10 = 0.1 × 1.8
N₁ × 10 = 0.18
N₁ = 0.18 / 10
N₁ = 0.018 N

Alkalinity = 0.018 × 50 × 1000 mg/l
           = 900 ppm

Result

Alkalinity of phenolphthalein = 1600 ppm
Total Alkalinity of methyl orange = 900 ppm

m = (P - T)
m = 700 ppm   Methyl orange alkalinity

Sustainable Development of Alkalinity of Water

Safe drinking water – Maintains appropriate pH and buffering capacity (supports SDG 6 – Clean Water and Sanitation).
Healthy aquatic ecosystems – Proper alkalinity supports biodiversity and prevents harmful pH shifts.
Efficient agricultural practices – Balanced alkalinity enhances soil health and crop yield.
Reduced chemical use – Avoids over-treatment with acids or bases (supports SDG 12 – Responsible Consumption and Production).
Improved industrial water management – Less corrosion and scaling, extending equipment lifespan and reducing resource consumption.

Experiment 3: Argenometric Titration

Indicator Used (Potassium chromate)

Titration Process

Flow chart

10 ml water sample
N/100 AgNO₃ solution
Add 2-3 drops of Potassium Chromate indicator

Before Titration

Take 10 ml of the water sample in a conical flask.
Add 2-3 drops of potassium chromate indicator (yellow color).
This acts as an indicator for the endpoint of chloride titration.

During Titration

Titrate with N/100 AgNO₃ solution.
White precipitate of silver chloride (AgCl) forms initially.
Continue titration slowly.
Near the endpoint, a light reddish-brown color appears (due to silver chromate formation).
Record burette reading (Volume of AgNO₃ used).

End Of Titration

Endpoint: permanent light reddish-brown color.
All chloride ions have reacted.

Aim

Determination of chloride content in a given wetter sample wing argenometric titration.

Requirement

0.01N AgNO₃, k₂CrO₄^–indicator, 10 ml water sample, burette, measuring cylinder, beaker, conical flask.

Theory

Precipitation titrations involves the formation of an insoluble precipitate when the reacting solutions are mixed together for example, when a solution of silver nitrate is added to a solution of sodium chloride, a white precipitate of silver chloride is formed.

AgNO₃+ NaCl -> AgCl+ NaNO₃

Q. Why this method is known as Mohr’s method ?

Mohr’s Method’s This method determines the chloride ion concentration of a solution by titration with silver nitrate. As the silver nitrate solution is slowly added, a precipitate of silver chloride forms. Ag+ reacts with CI- to give a white precipitate of AgCl and not Ag2CrO4 as the solubility product of sliver chloride is less than that of silver chromate.

Ag+ CI -> AgCl

As the endpoint or the equivalence approaches, Ag+ may also react prematurely with CrO4 present in the solution as an indicator to form a red precipitate of Ag2CrO4. This precipitate, however, dissolves on shaking as long as Cl- ions are present in solution .

2 Ag+ + CrO₄^– -> Ag₂CrO₄(red ppt)

Ag₂CrO₄+ 2Cl- -> 2AgCl+ CrO₄^2-

When all the chloride ions have reacted with AgNO₃, a slight excess of AgNO₃ now added reacts with potassium chromate to give a red ppt of silver chromate. The reaction between AgNO₃ and NaCl can be quantitatively carried out in a neutral medium in this method of estimation, since silver hydroxide gets precipitated in alkaline medium leading to mistaken results and in acidic medium, Some chromate is converted to dichromate due to which red precipitate will not form.

This method can be used to determine the chloride ion concentration of water samples from many sources such as sea water, stream water, river water and estuary water.

Observation Table

Trial	Initial Reading (mL)	Final Reading (mL)	AgNO3 (V₂ in mL)
1	0.0	5.2	5.2
2	5.2	9.4	4.2
3	9.4	14	4.6
Average				4.87

Formula Used

(Normality of solution)N₁= (N₂x V₂) /10
Amount of chloride (ppm) = N₁ x 35.5 x 1000

Calculations

(Normality of solution) N₁ = 0.01 x 4.87 / 10
= 0.00487 M
Amount of Chloride = 0.00487 x 35.5 x 1000
= 172.885 ppm

Result

Strength of chloride content in water sample was found to be 172.885ppm

Argentometric Titration and Sustainable Development

Argentometric titration is a method where silver nitrate (AgNO₃) is used to determine concentrations of halides (like chloride, bromide, iodide) by precipitation. It connects to sustainable development mainly through:

Aspect	Interaction with Sustainable Development
Water Quality Monitoring	Argentometric titration is commonly used to test chloride levels in drinking water, rivers, and seas. Monitoring water quality supports SDG 6: Clean Water and Sanitation.
Industrial Wastewater Treatment	It helps industries check chloride content in waste before discharge, promoting environmentally safe practices under SDG 12: Responsible Consumption and Production.
Reduction of Harmful Reagents	Modern argentometric methods aim to use minimal silver nitrate (toxic and expensive), aligning with green chemistry principles that promote sustainability.
Education and Awareness	Teaching sustainable laboratory techniques like efficient titration methods supports SDG 4: Quality Education by integrating sustainability into science curricula.
Resource Efficiency	Precise methods avoid wastage of silver, an important natural resource, supporting SDG 12 again (efficient resource use).

In Short

Argentometric titration supports sustainable development by helping monitor and protect water resources, encouraging greener lab practices, and promoting responsible resource use.

Experiment 4: Determination of Viscosity Using Ostwald’s Viscometer

1. Flow chart

Fill Viscometer: Add 10 ml of distilled water to viscometer flask.
Water Bath: Place viscometer in a constant temperature water bath.
Measure Time (t₁): Use stopwatch to measure flow time of water between two marks.
Refill with Test Liquid: Add 10 ml of test liquid into viscometer.
Measure Time (t₂): Measure the flow time of the test liquid using stopwatch.

2. Before Titration

Clean and dry viscometer properly.
Add 10 ml of distilled water.
Place viscometer in a constant temperature water bath.
Raise water above upper mark using suction and measure time t₁.

3. During Titration

Clean viscometer and add 10 ml of test liquid.
Place viscometer in the same water bath.
Suck liquid above upper mark and note time t₂.
Repeat for accuracy.

Use formula

η₂ / η₁ = (d₂ / d₁) × (t₂ / t₁)
Where:
- η = Viscosity
- d = Density
- t = Flow Time

Aim

To determine the viscosity of a given liquid sample solution using Ostwald’s viscometer.

Requirement

Ostwald’s viscometer (glass capillary viscometer)
Water
Liquid sample
Stop-watch

Theory

The Ostwald’s viscometer method is based on Poiseuille’s equation:

η = (πr⁴tP) / (8Vl)
Where:
η = Viscosity of the liquid
V = Volume of the liquid
t = Flowing time (in seconds)
r = Radius of the capillary tube
l = Length of liquid column
P = Hydrostatic pressure of the liquid

A simple comparative method is used where the viscosity of an unknown liquid is calculated relative to a known liquid (usually water):
η_r = η_solution / η_solvent = (ρ_solution × t_solution) / (ρ_solvent × t_solvent)

For very dilute solutions, ρ_solution ≈ ρ_solvent, so:
η_r = t_solution / t_solvent

Procedure:

Rinse the viscometer with water.
Add about 20 mL of water into the wide arm of the viscometer.
Blow through the wide arm until the water rises above the mark.
Ensure there are no air bubbles present.
Allow the liquid to fall through the capillary, start the stop-watch, and note the time taken for water to flow between the two marks.
Repeat the same steps with the given liquid sample.

Observation Table

S.No.	Flow Time (s) - Water	Flow Time (s) - Given Solution
1
2
3
Mean (Average Time)

Calculations

Weight of empty bottle = 5.4 g
Weight of bottle + water = 24.4 g → Weight of water = 19.0 g
Weight of bottle + liquid = 25.5 g → Weight of liquid = 20.1 g
Density of liquid = (Weight of liquid × ρ_water) / Weight of water
ρ_water = 1 g/cm³, η_water = 0.01 Poise
η_liquid = (ρ_liquid × t_liquid × η_water) / (ρ_water × t_water)

Result

The viscosity of the given liquid solution = _____ Poise

How It Supports Sustainability

Eco-Friendly Material Design: Supports the use of biodegradable fluids to replace petrochemicals.
Energy Efficiency: Optimized viscosity reduces energy usage during processing and transport.
Water Treatment: Helps manage sludge flow, reducing water and chemical usage.
Process Optimization: Fine-tunes industrial operations for reduced waste and better efficiency.
Safe Transport: Prevents leaks and accidents through proper fluid handling.

Conclusion

Viscosity measurement contributes to sustainability by enhancing efficiency, reducing waste, and enabling cleaner technologies

Experiment 5: Determination of Surface Tension using Drop Number Method

Flow Chart

Fill Pipette: Fill pipette with distilled water using a beaker.
Count Water Drops: Count the number of drops (n₁) from pipette tip.
Refill with Test Liquid: Replace water with test liquid in the same pipette.
Count Test Liquid Drops: Count the number of drops (n₂) from test liquid.

Before Experiment

Clean and dry the dropper/pipette.
Fill with distilled water.
Set up the drop counting apparatus.
Maintain a constant temperature environment.

During Experiment

Count number of drops (n₁) for a fixed volume (e.g., 10 ml) of water.
Replace water with test liquid.
Count number of drops (n₂) for the same volume.
Repeat the experiment for accuracy.

Use formula

γ = Surface tension
d = Density
n = Number of drops counted
γ₂ = γ₁ × (n₁ / n₂) × (d₂ / d₁)
Where:
Result: Surface tension of the given liquid is calculated using the above formula.

Aim

To determine the surface tension of a given liquid by the drop number method.

Requirements

Stalagmometer
Water
Liquid sample
Beaker

Theory

Surface tension is the force per unit length acting along the surface of a liquid, measured in dynes/cm (CGS) or N/m (SI). When a liquid is allowed to drip slowly from a stalagmometer, the number of drops formed is inversely proportional to its surface tension. The surface tension of the given liquid is calculated using the formula:

γ₂ = (n₁ × ρ₁ × γ₁) / (n₂ × ρ₂)

Where:

- γ₁ = Surface tension of water
- γ₂ = Surface tension of the liquid
- n₁ = Number of drops of water
- n₂ = Number of drops of liquid
- ρ₁ = Density of water
- ρ₂ = Density of the liquid

Procedure

Clean the stalagmometer with chromic acid.
Immerse its lower end in distilled water and suck up water to mark A.
Let the water flow out and count drops between marks A and B.
Repeat to obtain three readings.
Clean and dry the stalagmometer, then fill it with the test liquid.
Let it flow out and count the drops.
Weigh empty specific gravity bottle (W₁).
Fill with water, weigh (W₂).
Empty, dry, fill with test liquid, and weigh again (W₃).

Observation Table

S.No.	No. of Drops (Water)	No. of Drops (Liquid)
1	56	65
2	56	65
3	56	65
Mean	56	65

Calculations

W₁ (Empty bottle) = 5.5 g
W₂ (Bottle + Water) = 23.3 g → Weight of water = 17.8 g
W₃ (Bottle + Liquid) = 24.4 g → Weight of liquid = 18.9 g
Relative density = (W₃ – W₁) / (W₂ – W₁) = 18.9 / 17.8
γ_water = 72.14 dyne/cm
γ_liquid = (18.9 × 56 × 72.14) / (17.8 × 65) = 65.9922 dyne/cm

Result

The surface tension of the given liquid solution = 65.9922 dyne/cm

What is Surface Tension?

Surface tension is the cohesive force between liquid molecules at the surface. It’s responsible for phenomena like water droplets forming beads and insects walking on water.
♻️ Sustainability Connections:
- Water Purity Testing: Surface tension changes indicate presence of pollutants, helping monitor clean water initiatives.
- Eco-Detergents: Aids development of biodegradable soaps and surfactants with minimal environmental harm.
- Reduced Chemical Use: Understanding surface behavior helps optimize processes like painting and coating, lowering waste.
- Green Nanotechnology: Surface tension helps create sustainable nano-solutions for medicine and agriculture.
- Oil Spill Cleanup: Used in the formulation of eco-friendly dispersants and cleanup agents.

🌱 Conclusion

The surface tension experiment supports sustainability by enabling cleaner industrial processes, improving environmental monitoring, and fostering eco-innovation.

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