CBSE Biology Experiment - Collection of Water from Two Different Water Bodies and Study of pH, Presence of Living Organisms
Everything around us has a pH like pH of lemon is 2, pH of blood is 8.
Table of Contents
Aim
Apparatus Required
Theory
Procedure
Observation
Result
Precautions
Lab Manual Questions
Viva Questions
Practical Based Questions
Summary
Frequently Asked Questions
Aim
To study pH and find the presence of organisms in water bodies.
Apparatus Required
Water samples from ponds and lakes.
Test tubes
Slides
Compound Microscope
FAA(Formalin Aceto Alcohol)
pH paper strip
Beakers
Theory
Numerous plants and animals that live in water have special adaptations that help them thrive there. Turbidity, pH, and the variety of plants and animals, as well as their density, are a few of the factors that affect the quality of water. Acidic solutions are those with a pH under 7, and basic solutions are those with a pH over 7. At 25°C, pure water has a pH of 7. A pH metre can be used to calculate the pH of a water sample using the indicator dye method and the electrometric method.
Procedure
pH
Fill two clean beakers with a small amount of water from each sample, and then label the beakers A and B.
Place a little piece of paper with a wide pH range in each sample of water.
Compare the colour of the pH paper strip to the chart of typical pH values. This provides a rough pH.
Once more, compare the pH scale of the pH paper with the colour of the paper.
This will provide the accurate pH value for the water samples.
To Detect Presence of Organisms:
Collect the water samples.
Add 5 ml of FAA.
Leave the sample for 48-72 hours.
Transfer the sediments deposited into test tubes and label it.
From the test tube transfer a drop of samples to the slides and fix it in the compound microscope.
Observe the slides from lower to higher magnification.
Observation
With the colour change of the pH paper strip ,the pH of the water samples are identified.
Different types of organisms present are recorded.
Result
A natural solution's pH value of 7 indicates that the water sample is neutral.
Water samples are considered to be alkaline if the pH of a basic solution is more than 7.
Water samples are acidic by nature if the pH of an acidic solution is lower than 7.
Different organisms are identified and observed.
Precautions
Use test tubes or beakers that are dry and clean for your investigations.
Use a different dropper for each sample of water.
Let the pH paper dry completely before comparing the colour to the colour wheel.
Carefully match the hue and precisely calculate the pH.
Carefully handle the microscope.
Lab Manual Questions
1. Why do you find few organisms in polluted water.Explain.
Ans:Polluted water can lead to destruction of organisms by spreading diseases from one organism to another.So few organisms are found in polluted water.
2. Why is the FAA added after collecting the water sample?
Ans:FAA is used in water samples for the preservation of organisms present in the sample.
3. Name at least one phytoplankton and zooplankton commonly found in polluted water.
Ans:Phytoplankton found in polluted water-blue green algae,diatoms.
Zooplankton found in polluted water-protozoans,tiny fish.
Viva Questions
1. Why water is necessary for living organisms?
Ans: Plants need water for photosynthesis(process of making their own food)and animals need water for metabolic processes.
2. What are the water bodies around us?
Ans: Oceans,lakes,rivers,seas,glaciers are the water bodies around us.
3. What type of microorganisms are found in pond water?
Ans: Bacteria,microalgae,protozoans are microorganisms found in pond water.
4. What do you mean by pOH?
Ans: Potential of hydroxide ion is used to measure hydroxyl concentration in a solution.
5. What is the pH of an acidic solution?
Ans: Below 7.0 in a pH scale is an acidic solution.
6. What is the effect of dilution on the pH of an alkaline solution?
Ans: When an alkaline solution is diluted,oh ions concentration will decrease.Thus pH of alkali decreases.
7. Define pH.
Ans: pH is the measure of concentration of hydrogen ions in a solution.
8. What does the pH of a solution signify?
Ans: pH of a solution signifies the acidity or basicity of a solution.
9. Who invented pH?
Ans: In 1909,Sorensen invented the concept of pH.
10. Organisms live between which pH range?
Ans: Most organisms live between 6.5-.5 pH range.
Practical Based Questions
The pH of pure water is neutral,the best explanation for this is
The pH of pure water is 7
In pure water the concentration of hydrogen and hydroxide ions are same
Water do not contain free hydrogen and hydroxide ions
Water will never ionise.
Ans: B.In pure water the concentration of hydrogen and hydroxide ions are same.
2.The normal pH of blood is
A.7.0
B.7.2
C.7.3
D.7.4
Ans: D.7.4
3.Which of the following is an example of an amphoteric molecule?
A. Acetic acid
B. Malic acid
C. Sugars
D. Water
Ans: D. Water
4.What is the full form of pH?
A.Positive hydrogen
B.Potential hydrogen
C.Positron
D.Proton of hydrogen
Ans: B.Potential hydrogen
5.In presence of an acid,amino group can be
A.Polarized
B.Washed away
C.Protonated
D.Replaced
Ans: C.Protonated
6.Why does ice float in water?
A.Because of stronger hydrogen bonds at the surface
B.The density of water as a solid is less than the density of water as a liquid
C.Surface tension helps it float
D.It is more dense
Ans: B.The density of water as a solid is less than the density of water as a liquid
7.Pollution causes the pH of rainwater to fall below 6.What is such type of rain called?
A.Acid rain
B.Polluted rain
C.Low pH rain
D.Non point source pollution
Ans: A.Acid rain
8.According to the pH range which substance is more acidic than lemon juice.
A.Hydrochloric acid
B.Cabbage
C.Milk
Ans: A.Hydrochloric acid
9.Upper part of sea/aquatic ecosystem contains:
A.Plankton
B.Nekton
C.Benthons
D.None of the above
Ans: A.Plankton
10.The second trophic level in a lake is
A.Fungi
B.Benthos
C.Zooplankton
D.Phytoplankton
Ans: C.Zooplankton
Summary
The pH of the two different water samples are identified using a pH paper strip.
The organisms in the water bodies are identified using a microscope.
FAQs on Collection of Water from Two Different Water Bodies and Study for pH and Presence of Living Organisms
1. Why is the pH value measured between 0 and 14?
The pH scale does not range from 0 to 14. The majority of frequently encountered solutions have pH values that fall within this range. pH values may fall within or exceed this range. The negative base -10log of the concentration of hydrogen ions in a solution is the general definition of the pH value of a solution. The pH value would alter as a direct result of the temperature's impact on the equilibrium and dissociation rates. Water, for instance, would express a different pH at a different temperature than it does at ambient temperature, where it displays a pH value of 7.
2. Write about biological applications of pH?
It provides a qualitative measurement for a number of issues in cell biology and associated domains.In addition to the small molecules we have just talked about, macromolecules also include proton dissociable groups.The cell environment is buffered at a constant pH of around 7.Changes in the pH around the macromolecule will influence which groups are protonated and which are not, which in turn determines the characteristics of the molecule. Experiments like biological enzymatic assays require a specific pH. Enzymes, which are proteins that serve as catalysts for significant biological events, are particularly in need of this. Most enzymes can only function within a narrow pH range.
3. What causes high pH?
If the pH of a body of water exceeds 9 frequently or for extended periods of time, it is deemed to have a high pH. Since anthropogenic sources are more frequently acidic than basic, high pH is less frequently identified as a probable cause than low pH.Damage to the eyes, gills, skin, and olfactory organ.When high pH is chosen as a candidate cause, take the following associated factors:
diffuse oxygen
Ionic potency: The pH mostly regulates the chemical structure and solubility of ionic substances.
4. What is pH in the body?
Our body pH can vary greatly from one location to another, with the stomach having the highest levels of acidity (pH 1.35 to 3.5) to support digestion and guard against opportunistic microorganisms. But even in the stomach, the layer immediately adjacent to the epithelium is very fundamental in order to prevent mucosal damage. Duodenal ulcers may be significantly influenced by decreased stomach lining secretion of bicarbonates and a decrease in the alkaline/acid secretion in duodenal ulcer patients . The skin's high acidity (pH 4-6.5) creates an acid mantle that serves as a barrier against microbial proliferation in the environment.
