Final answer:
To find the molarity of a 2.1% w/v C2H6O solution, convert the mass to moles using the molar mass, and then divide by the volume. The molarity is calculated to be 0.456 M, which does not match any of the provided answers, indicating a possible error in the question or answer choices.
Step-by-step explanation:
The question asks to convert a 2.1% (w/v) C2H6O (ethanol) solution to molarity (mol/L). To find the molarity, we first need to convert the given percentage concentration to grams per liter, then to moles per liter using the molar mass of C2H6O (46.07 g/mol). A 2.1% w/v solution means 2.1g of ethanol per 100 mL of solution. This is equivalent to 21g per liter since there are 1000 mL in a liter.
To calculate the molarity (M):
- Convert the mass of C2H6O to moles: 21g / 46.07g/mol = 0.456 mol
- Since the solution volume is 1 L, the molarity is simply the number of moles: 0.456 mol/L
Therefore, the correct molarity is 0.456 M, which is not one of the options provided, so there seems to be a mistake in the question or the answer choices. Note that none of the choices (A, B, C, D) matches the calculated molarity.