Ethanol is used widely as a solvent in laboratories for various chemical reactions. A laboratory technician takes 50.0 mL of ethanol and dilutes it to 100.0 mL with distilled water. What is the percentage concentration by volume of the resulting solution?

This question is quite vague, as the initial concentration of ethanol is not provided. However, from experience I can tell you that most laboratory work is done with 98% ethanol, and not absolute ethanol (100%). So in order to calculate the final concentration, we need to take the given values, which includes the initial concentration (98%), the initial volume (50.0mL) and the final volume (100.0mL). We apply the following equation to calculate the final concentration:

C1V1 = C2V2

C1 = Initial concentration

C2 = Final concentration

V1 = Initial volume

V2 = Final volume

(98%) (50.0mL) = (C2) (100.0mL)

Therefore, the final concentration (C2) = 49%

The answer is B 50% just finished the test