Explain the formation of scum when hard water is treated with soap.
Soap does not work properly when the water is hard. A soap is a sodium or potassium salt of long chain fatty acids. Hard water contains salts of calcium and magnesium. When soap is added to hard water, calcium and magnesium ions present in water displace sodium or potassium ions from the soap molecules forming an insoluble substance called scum. A lot of soap is wasted in the process.
Give a test that can be used to differentiate between saturated and unsaturated hydrocarbons.
Butanone is a four-carbon compound with the functional group
Draw the structures for the following compounds
$(i)$ Butanone $(ii)$ Hexanal
What are the two properties of carbon which lead to the huge number of carbon compounds we see around us ?
A mixture of oxygen and ethyne is burnt for welding. Can you tell why a mixture of ethyne and air is not used ?