The Hydrogen ion concentration of a pH 3.8 solution would be higher than that of a solution with a pH of 6.2. This is because since the pH scale measures the concentration of Hydrogen ions. We know that a pH range of less than 7 is considered acidic and greater than 7 is basic. If a solution is more acidic it would possess more hydrogen ions than if it weren't. In this case a pH value of 3.8 is more acidic than pH 6.2.
Sound wave is gathered by Pinna ; which is outer ear !!
So C is your answer !!
In the following reaction,76.616 litre of oxygen will react
(3.5mol)(24.106 g/1mol c6h6) =84.371 g C6H6
