(a) What is the difference between a substitution reaction and an addition reaction? Which one is commonly observed with alkenes and which one with aromatic hydrocarbons? (b) Using condensed structural formulas, write the balanced equation for the addition reaction of 2-pentene with Br2 and name the resulting compound. (c) Write a balanced chemical equation for the substitution reaction of Cl2 with benzene to make para-dichlorobenzene in the presence of FeCl3 as a catalyst.