(a) Write names and formulae of hydrocarbons containing a single and a double bond (one example for each). Give one characteristic chemical property of each.
(b) What is a detergent? Name one detergent.
(c) Why have detergents replaced soap as a washing agent?
(a) (i) Single bond: Methane, CH4. They are quite unreactive hence they undergo substitution reaction with chlorine in presence of sunlight.
(ii) Double bond: Ethene, CH2 = CH2. They undergo addition reaction in the presence of a catalyst like nickel or palladium.
(b) A detergent is the sodium salt of long chain benzene sulphonic acid which has cleansing properties in water.
Ex: Sodium n-dodecyl benzene sulphonate.
(c) Detergents are better cleansing agents than soaps because they do not form insoluble calcium and magnesium salts with hard water, and hence can be used for washing even with hard water.