In a titration of 0.5 M HCl and an unknown concentration NaOH, 25.0 ml of NaOH was required to completely neutralize 25.0 ml of HCl. What is the concentration of the NaOH?
To find the concentration of NaOH, we can use the equation:
Molarity (M) = moles of solute / volume of solution (L)
Step 1: Calculate the moles of HCl:
Moles of HCl = Molarity of HCl x Volume of HCl
Moles of HCl = 0.5 M x 0.025 L
Moles of HCl = 0.0125 moles
Step 2: Since the chemical equation for the reaction between HCl and NaOH is 1:1, the moles of NaOH required to neutralize the HCl are also 0.0125 moles.
Step 3: Calculate the concentration of NaOH:
Molarity of NaOH = Moles of NaOH / Volume of NaOH
Molarity of NaOH = 0.0125 moles / 0.025 L
Molarity of NaOH = 0.5 M
Therefore, the concentration of NaOH is 0.5 M.
To determine the concentration of the NaOH, we need to use the concept of stoichiometry. The balanced chemical equation for the reaction between HCl and NaOH is:
HCl + NaOH → NaCl + H2O
From the equation, we can see that 1 mole of HCl reacts with 1 mole of NaOH to produce 1 mole of NaCl and 1 mole of water. This means that the ratio of mole to mole between HCl and NaOH is 1:1.
Given that 25.0 ml of 0.5 M HCl is completely neutralized by 25.0 ml of NaOH, we can determine the number of moles of HCl used in the reaction:
Moles of HCl = Volume of HCl (in liters) × Concentration of HCl
Since the volume is given in milliliters, we need to convert it to liters:
Volume of HCl = 25.0 ml = 0.025 liters
Now we can calculate the moles of HCl:
Moles of HCl = 0.025 L × 0.5 M = 0.0125 moles
Since the stoichiometry of the reaction is 1:1, the number of moles of NaOH used in the reaction is also 0.0125 moles.
Now, to find the concentration of NaOH, we need to divide the moles of NaOH by the volume of NaOH used:
Concentration of NaOH = Moles of NaOH / Volume of NaOH
In this case, the volume of NaOH used is 25.0 ml, which is equal to 0.025 liters:
Concentration of NaOH = 0.0125 moles / 0.025 L = 0.5 M
Therefore, the concentration of the NaOH is 0.5 M.