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?
A battery of 9 V is connected in series with resistors of 0.2 Ω, 0.3 Ω, 0.4 Ω , 0.5 Ω and 12 Ω, respectively. How much current would flow through the 12 Ω resistor?
A convex lens forms a real and inverted image of a needle at a distance of 50 cm from it. Where is the needle placed in front of the convex lens if the image is equal to the size of the object? Also, find the power of the lens.
An electric lamp of 100 Ω, a toaster of resistance 50 Ω, and a water filter of resistance 500 Ω are connected in parallel to a 220 V source. What is the resistance of an electric iron connected to the same source that takes as much current as all three appliances, and what is the current through it?
A hot plate of an electric oven connected to a 220 V line has two resistance coils A and B, each of 24 Ω resistance, which may be used separately, in series, or in parallel. What are the currents in the three cases?
How does the electronic configuration of an atom relate to its position in the Modern Periodic Table?
How is the equal genetic contribution of male and female parents ensured in the progeny?
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.
Name some sources of direct current.
What do you mean by a precipitation reaction? Explain by giving examples.