Which solution is the most concentrated?

A. [tex]$2.0 \, \text{mL}$[/tex] of [tex]$10 \, \text{M} \, \text{H}_2\text{SO}_4$[/tex], where [tex]$\text{H}_2\text{SO}_4$[/tex] has a molar mass of [tex]$98 \, \text{g/mol}$[/tex]

B. [tex]$5.0 \, \text{mL}$[/tex] of [tex]$1.0 \, \text{M} \, \text{PbSO}_4$[/tex], where [tex]$\text{PbSO}_4$[/tex] has a molar mass of [tex]$303 \, \text{g/mol}$[/tex]

C. [tex]$2.0 \, \text{mL}$[/tex] of [tex]$10.5 \, \text{M} \, \text{H}_2\text{O}_2$[/tex], where [tex]$\text{H}_2\text{O}_2$[/tex] has a molar mass of [tex]$34 \, \text{g/mol}$[/tex]

D. [tex]$100 \, \text{mL}$[/tex] of [tex]$10 \, \text{M} \, \text{NaCl}$[/tex], where [tex]$\text{NaCl}$[/tex] has a molar mass of [tex]$58 \, \text{g/mol}$[/tex]



Answer :

To determine which solution is the most concentrated, we compare the molarity of each solution. The concentration of a solution is typically expressed in terms of molarity (M), which is moles of solute per liter of solution. Here are the given concentrations for each solution:

1. \(2.0 \, \text{mL}\) of \(10 \, \text{M} \, \text{H}_2\text{SO}_4\)
2. \(5.0 \, \text{mL}\) of \(1.0 \, \text{M} \, \text{PbSO}_4\)
3. \(2.0 \, \text{mL}\) of \(10.5 \, \text{M} \, \text{H}_2\text{O}_2\)
4. \(100 \, \text{mL}\) of \(10 \, \text{M} \, \text{NaCl}\)

We'll compare these given molarity values directly:

1. The molarity of the \(\text{H}_2\text{SO}_4\) solution is \(10 \, \text{M}\).
2. The molarity of the \(\text{PbSO}_4\) solution is \(1.0 \, \text{M}\).
3. The molarity of the \(\text{H}_2\text{O}_2\) solution is \(10.5 \, \text{M}\).
4. The molarity of the \(\text{NaCl}\) solution is \(10 \, \text{M}\).

Since molarity directly indicates the concentration of the solution, the highest numerical value of molarity corresponds to the most concentrated solution.

Based on the given concentrations:

- \( \text{H}_2\text{SO}_4 \) has a molarity of \(10 \, \text{M}\).
- \( \text{PbSO}_4 \) has a molarity of \(1.0 \, \text{M}\).
- \( \text{H}_2\text{O}_2 \) has a molarity of \(10.5 \, \text{M}\).
- \( \text{NaCl} \) has a molarity of \(10 \, \text{M}\).

The highest molarity among these values is \(10.5 \, \text{M}\) which corresponds to the \(\text{H}_2\text{O}_2\) solution.

Therefore, the most concentrated solution is [tex]\(2.0\, \text{mL}\)[/tex] of [tex]\(10.5 \, \text{M} \text{H}_2\text{O}_2\)[/tex].