Question

A solution is prepared by dissolving 25.0 mL ethanol, CH3CH2OH (d=0.789 g/mL), in enough water to produce 250.0 mL solution. What is the molarity of ethanol in the solution?

Answer 1

The molarity = 1.716 M

Further explanation

Given

25 ml ethanol

d = 0.789 g/ml

250 ml solution

Required

The molarity

Solution

Molarity shows the number of moles of solute in every 1 liter of solute or mmol in each ml of solution

$\large{\boxed {\bold {M ~ = ~ \frac {n} {V}}}$

mass of ethanol :

= 25 ml x 0.789 g/ml

= 19.725 g

mol ethanol :

= 19.725 g : 46 g/mol

= 0.429

The molarity :

= 0.429 : 0.25 L

= 1.716 M