Question

Which of the following solutions have the same concentration ?

1. 4 g of NaOH in 250 mL of solution
2. 0.5 mol of KCl in 250 mL of solution
3. 40 g of NaOH in 250 mL of solution
4. 5.61 g of KOH in 250 mL of solution

• A. 1, 4
• B. 4 only
• C. All
• D. 1, 2

Answer 1

Answer:

A. 1, 4

To determine which solution has the same concentration, we need to calculate the molarity (M) of each solution.

Molarity (M) = Number of moles of solute / Liters of solution

First, let's calculate the number of moles of each solute:

• NaOH: 4 g / 40 g/mol = 0.1 mol

• KOH: 5.61 g / 56.1 g/mol = 0.1 mol

Now, let's calculate the molarity of each solution:

• NaOH: 0.1 mol / 0.250 L = 0.4 M

• KOH: 0.1 mol / 0.250 L = 0.4 M

Both solutions have the same molarity (0.4 M), which means they have the same concentration.