Soaps are salts of fatty acids. Common soaps are water soluble sodium and potassium salts of fatty acids. Soap cannot form lather unless it dissolves in water. Hard water does not dissolve soap because the calcium and magnesium salts present in it produce insoluble substances by reacting with soap. These insoluble substances separate out as scum and reduce the effectiveness of the soap as a cleansing agent.
Category Chemistry
Why is there a scent after it rains on parched soil?
The peculiar smell is produced by the soil inhabiting bacteria called streptomycetes. Streptomycetes are abundant in dry warm soil – a million of them are present in a pinch of soil. They release compounds such as geosmin and 2-methyl isoborneol, which vapourize easily, when wetted by rain water after a dry spell. That is why we get the musty odour only after the first rain of the rainy season. The smell can be detected in a newly ploughed field also.
Why do the dry beds of ponds and lakes crack?
The bottom of lakes and ponds, which usually hold still water, is usually covered with sediments formed of clay material. Clay contains chemical substances such as sodium bentonite which have the property of expanding when wet. The loss of moisture, therefore, makes this layer of clay shrink resulting in cracks on its surface. Thus, in summers when lakes and ponds go dry, the surface of their beds shows large cracks.
What are the different types of handshakes?
When you meet another person, or are introduced to him, it is polite to say ‘Namaste’ with folded hands, or extend your hand for a handshake. The handshake is the universal form of greeting in the West. However, even this simple gesture varies from country to country.
The American style handshake has a firm grip along with two quick pumps, eye contact and a smile. Variations in handshakes are based on cultural differences, not on personality or values. The Japanese give a light handshake. Germans offer a firm handshake with one pump, and the French grip is light with a quick pump. Middle Eastern people will continue shaking your hand throughout the greeting. Don’t be surprised if you are occasionally met with a kiss, a hug, or a bow somewhere along the way!