Aldehyde (Organic Salt Analysis)

AIM – To test the presence of aldehyde in the given organic compound.

Preliminary Test:-

Experiment Observation Inference
Added bromine water to solution No Effect Compound is saturated.
Or Or
Pink colour of Bromine water changed to colourless. Compound is unsaturated.
Added drop of blue Litmus to solution. No Effect. Carboxylic Acid and Phenol absent.
Added a few drops 2,4-dinitrophenylhydrazine to the solution. Yellowish -orange precipitate formed. Aldehyde or ketone may be present.

Confirmatory Test:-

Experiment Observation Inference
Added a few drops of Fehling’s solution A & B. Formation Of red colour. Aldehyde confirmed.

Chemical Equations:-

R3C-CR3 + Br2 –> No Effect

OR

R2C=CR2 + Br2  –>  BrR2C-CR2Br

R-CHO + (NO2)2C6H3NHNH2 –>  (NO2)2C6H3NHN=CRH (Yellowish Orange) + H2O

RCHO + 2Cu2+ + 2H2O –> RCOOH + Cu2O(Red) + 4H+

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Alcohol (Organic Salt Analysis)

AIM – To test the presence of alcohol in the given organic compound.

Preliminary Test:-

Experiment Observation Inference
Added bromine water to solution No Effect Compound is saturated.
Or Or
Pink colour of Bromine water changed to colourless. Compound is unsaturated.

Confirmatory Test:-

Experiment Observation Inference
Warmed with acetic acid and a few drops of concentrated sulphuric acid. Fruity smell is formed. Alcohol confirmed.

Chemical Equations:-

R3C-CR3 + Br2 –> No Effect

OR

R2C=CR2 + Br2  –>  BrR2C-CR2Br

CH3COOH + ROH –> CH3COOR + H2O

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Plasmolysis and Deplasmolysis in Peels of Rhoeo Leaf in Hypertonic and Hypotonic Solution Using Sodium Chloride

AIM: To demonstrate plasmolysis and de-plasmolysis in peels of Rhoeo leaf in hypertonic and hypotonic solution using sodium chloride.

REQUIREMENTS: Rhoeo leaf, glass slides, cover slips, dropper, sodium chloride, filter paper

THEORY: When a plant cell is placed in a concentrated salt solution, water from the cell sap flows out due to exosmosis.

The loss of water from the cell sap causes contraction or shrinkage of the protoplasm since the cell wall is firm and less elastic, it cannot keep pace with the contraction of the plasma membrane. Ultimately, the protoplasm separates from the cell wall and assumes a spherical shape. It is called plasmolysis

When a plasmolyzed cell is placed in water or hypertonic solution it absorbs water due to endosmosis and its protoplasm assumes the original shape it is called de-plasmolysis.

Plasmolysis is, this can be defined as the shrinkage of the protoplast of a cell from its cell wall due to exosmosis in a hypertonic solution.

OBSERVATION: the cell in dilute solution appears turgid due to endosmosis while the cells in concentrated shows plasmolysis due to exosmosis.

When the concentrated solution is replaced with water the protoplast of cells require its original shape,

PRECAUTIONS: The peel should not be exposed or dried.
The slide should be kept dry by removing extra solution with the filter paper.

DEMONSTRATION OF PLASMOLYSIS AND DEPLASMOLYSIS

Turgid Cells in Hypotonic Solution
Turgid Cells in Hypotonic Solution

 

Plasmolysed & Deplasmolysed Cells in Hypertonic solution

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Distribution of stomata on the dorsal and ventral side of a monocot leaf

AIM: To study the distribution of stomata on the dorsal and ventral side of a monocot leaf and to calculate the stomata index.

REQUIREMENT: Fresh leaf of any herbacious plant, cover slips, glass slides, methylene blue, dropper, water.

THEORY: Stomato are microscopic pores present in the epidermis of leaves and young shoots of plants.

They are chiefly concerned with the exchange of gases during photosynthesis and respiration.

They are also responsible for the loss of water during transpiration.

Each stomato has a slit like opening called stomata pore, which is surrounded by 2 spherical kidney shaped indirect leaves and dumbbell shaped in monocot leaves cells called guard cells.

PROCEDURE: Take a monocot leaf and from the dorsal surface of the leaf carefully peel out the epidermis of the leaf.

Carefully put it on the glass slide and add 2 to 3 drops of methylene blue so that the stomata could be identified.

Add a few drops of water to remove the excess colour and carefully put a cover slip at an angle of 45 degrees to avoid air bubbles.

Now observe the slide under the microscope and repeat the procedure for the ventral side as well.

OBSERVATION: 

MONOCOT LEAF
DORSAL 13-16
VENTRAL 20-23

PRECAUTIONS: The cutting of peel should be avoided.

Always use filter paper to remove the excess of methylene blue.

Use the brush to transfer the pills from water glass to the slide.

Air bubbles must be avoided.

Single Stomata
Single Stomata

 

Stomata in the epidermis of monocot leaf
Stomata in the epidermis of monocot leaf.

 

 

 

 

 

 

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