Question

What is the molarity of an aqueous solution of ethyl alcohol ($C{H}_{3}C{H}_{2}OH$, molar mass $=46.0$ $gmo{l}^{-1}$) which contains 50.0 g of alcohol in 500 mL of the solution?

• A. 2 $mol{l}^{-1}$
  
• B. 2.18 $mol{l}^{-1}$
  
• C. 2.11 $mol{l}^{-1}$
  
• D. None of these

Answer 1

Answer: (B)

2.18 $mol{l}^{-1}$

molar mass of ethyl alcohol = $46.0g/mole$

volume of solution = 500 ml

= $0.5l$

molarity = mole /volume of solution

mole of ethyl alcohol = $50/46$

molarity = (50/46)/ 0.5= 2.1739

molarity is $2.18$ (B)