Which solution has the highest concentration of NaCl? A. 175 g NaCl in 1.0 L B. 58.5 g NaCl in 1.5 L C. 29.3 g NaCl in 0.5 L D. 2.5 mol NaCl in 2.0 L E. 5.0 mol NaCl in 3.0 L

The answer is E. 5.0 mol NaCl in 3.0 L

The mass concentration (c) is the mass of the solute (m) divided by the volume of the mixture (V):

c = m/V

Now, let's go through all choices:

A. m = 175 g NaCl

V = 1.0 L

c = m/V = 175 g/1.0 L = 175 g/L

B. m = 58.5 g NaCl

V = 1.5 L

c = m/V = 58.5 g/1.5 L = 39 g/L

C. m = 29.3 g NaCl

V = 0.5 L

c = m/V = 29.3 g/0.5 L = 58.6 g/L

D. M = 2.5 mol NaCl

Since we have moles, and not grams, first we must calculate molar mass of NaCl which is the sum of atomic masses of the elements:

Mr (NaCl) = Ar (Na) + Ar (Cl) = 22.99 g + 35.45 g = 58.44 g

This means that in 1 mol there is 58.44g/L. So, in 2.5 mol there will be:

1 mol : 58.44 g/L = 2.5 mol : x

x = 2.5 * 58.44 g/L = 146.1 g/L

E. We will use the calculation from choice D.

Mr (NaCl) = 58.44 g.

In 1 mol there is 58.44g/L, so in 5 mol there will be:

1 mol : 58.44 g/L = 5 mol : x

x = 58.44 * 5 = 292.2 g/L

Therefore:

E > A > D > C > B