Why does micelle formation take place when soap is added to water? Will a micelle be formed in other solvents such as ethanol also?
A soap is a sodium or potassium salt of long chain carboxylic acids. It has one polar end and one non-polar end. The polar end is hydrophilic in nature which is attracted towards water. The non-polar end is hydrophobic but lipophilic, i.e., it is attracted towards hydrocarbons. When soap is added to water, soap molecules arrange themselves in a cluster, the non-polar portion out of water such that the non-polar ends are in the interior of the cluster attached with dirt and the polar ends are on the surface of the cluster. Since the dirt present on clothes is oily in nature and insoluble in water, the hydrophobic ends of the clusters attach themselves to the dirt. This cluster of soap molecule formation in which the dirt is entrapped is called micelles.
Micelle formation does not occur in alcohol because the alkyl chain of soap becomes soluble in alcohol.
Draw the structure for the following compounds.
(i) Ethanoic acid (ii) Bromopentane*
(iii) Butanone (iv) Hexanal.
*Are structural isomers possible for bromopentane?
What is an homologous series? Explain with an example.
How would you name the following compounds?
(i) CH3 -- CH2 -- Br
(ii)
(iii)
What will be the formula and electron dot structure of cyclopentane?
Explain the nature of the covalent bond using the bond formation in CH3Cl.
Why are carbon and its compounds used as fuels for most applications?
How many structural isomers can you draw for pentane?
Explain the mechanism of the cleaning action of soaps.
What are the two properties of carbon which lead to the huge number of carbon compounds we see around us?
Explain the formation of scum when hard water is treated with soap.
Did Döbereiner’s triads also exist in the columns of Newlands’ Octaves? Compare and find out.
What is a good source of energy?
Why is diffusion insufficient to meet the oxygen requirements of multi-cellular organisms like humans?
What are trophic levels? Give an example of a food chain and state the different trophic levels in it.
What changes can you make in your habits to become more environment-friendly?
What is the difference between a reflex action and walking?
What is the importance of DNA copying in reproduction?
If a trait A exists in 10% of a population of an asexually reproducing species and a trait B exists in 60% of the same population, which trait is likely to have arisen earlier?
Why should a magnesium ribbon be cleared before burning in air?
Define the principal focus of a concave mirror.
Will the impact of removing all the organisms in a trophic level be different for different trophic levels? Can the organisms of any trophic level be removed without causing any damage to the ecosystem?
What is the need for a system of control and coordination in an organism?
Explain different ways to induce current in a coil.
An object 5 cm in length is held 25 cm away from a converging lens of focal length 10 cm. Draw the ray diagram and find the position, size and the nature of the image formed.
Will geographical isolation be a major factor in the speciation of an organism that reproduces asexually? Why or why not?
How does the electronic configuration of an atom relate to its position in the Modern Periodic Table?
The magnification produced by a plane mirror is +1. What does this mean?
Draw a schematic diagram of a circuit consisting of a battery of three cells of 2 V each, a 5 Ω resistor, an 8 Ω resistor, and a 12 Ω resistor, and a plug key, all connected in series.
Under what soil condition do you think a farmer would treat the soil of his fields with quick lime (calcium oxide) or slaked lime (calcium hydroxide) or chalk (calcium carbonate)?
Oil and fat containing food items are flushed with nitrogen. Why?