Question

A solution of ethanol in water is 10% by volume. If the solution and pure ethanol have densities of 0.9866 g/cc and 0.785 g/cc respectively. The percent by weight is nearly?

• A. 7.95%
• B. 17%
• C. 9.86%
• D. 16.2%

Answer 1

The correct option is A 7.95%

Volume of ethanol = 10 ml

Volume of solution = 100 ml

Weight of ethanol = $Volume\times density$

= $10\times 0.785$

= 7.85 g

Weight of solution = $100\times 0.9866$

= 98.66 g

Weight percent of ethanol = $\frac{7.85}{98.66}$ $\times 100$

= $7.95\%$