Why are carbon and its compounds used as fuels for most applications?

38 Why have detergents replaced soap as a washing agent ? 39 (a) How does ethanoic acid react with sodium hydrogencarbonate? Give equation of the reaction which takes place. 39 Which of the two is better for washing clothes when the water is hard: soap or detergent? Give reason for your answer. 40 What is meant by a substitution reaction? Give an example (with equation) of the substitution reaction of an alkane.