What is the concentration of a solution if 5 g of NaOH is dissolved in 250 mL of
Practice Questions
Q1
What is the concentration of a solution if 5 g of NaOH is dissolved in 250 mL of water? (2020)
0.5 M
1 M
0.2 M
0.1 M
Questions & Step-by-Step Solutions
What is the concentration of a solution if 5 g of NaOH is dissolved in 250 mL of water? (2020)
Step 1: Find the molar mass of NaOH. Sodium (Na) is about 23 g/mol, Oxygen (O) is about 16 g/mol, and Hydrogen (H) is about 1 g/mol. So, NaOH = 23 + 16 + 1 = 40 g/mol.
Step 2: Calculate the number of moles of NaOH. Use the formula: Moles = mass (g) / molar mass (g/mol). Here, Moles = 5 g / 40 g/mol = 0.125 mol.
Step 3: Convert the volume of the solution from mL to L. Since 1 L = 1000 mL, 250 mL = 250 / 1000 = 0.25 L.
Step 4: Calculate the molarity (concentration) of the solution. Use the formula: Molarity (M) = moles of solute / volume of solution (L). Here, Molarity = 0.125 mol / 0.25 L = 0.5 M.
