Suppose a student adds 25.00 mL of 1.025 M HCl to a 1.50 g antacid tablet. The student boils and then titrates the resulting solution to the endpoint with 0.4969 M NaOH. The titration requires 21.3 mL NaOH to reach the endpoint. How many moles of HCl were neutralized by the NaOH?

mols NaOH = M x L = ?

mols HCl = mols NaOH.

To determine the number of moles of HCl neutralized by NaOH, we need to calculate the number of moles of NaOH used in the titration.

Step 1: Calculate the number of moles of NaOH used:
Moles NaOH = Volume NaOH (in L) x Concentration NaOH (in M)

Given:
Volume NaOH = 21.3 mL = 21.3/1000 L = 0.0213 L
Concentration NaOH = 0.4969 M

Moles NaOH = 0.0213 L x 0.4969 M = 0.0106 mol NaOH

Step 2: Determine the stoichiometry between HCl and NaOH using the balanced chemical equation:
HCl + NaOH -> NaCl + H2O

From the balanced equation, we can see that 1 mole of HCl reacts with 1 mole of NaOH.

Step 3: The number of moles of HCl neutralized is equal to the number of moles of NaOH used:
Moles HCl = 0.0106 mol NaOH

Therefore, 0.0106 moles of HCl were neutralized by the NaOH.

To find the number of moles of HCl neutralized by NaOH, we can use the concept of stoichiometry. The balanced equation for the reaction between HCl and NaOH is:

HCl + NaOH -> NaCl + H2O

From the balanced equation, we can see that one mole of HCl reacts with one mole of NaOH.

First, let's calculate the number of moles of NaOH used in the titration. We can do this by multiplying the volume of NaOH used (21.3 mL) by the molarity of NaOH (0.4969 M):

Number of moles of NaOH = (Volume of NaOH used) x (Molarity of NaOH)
= 21.3 mL x 0.4969 M

To convert milliliters to liters, divide by 1000:

Number of moles of NaOH = 0.0213 L x 0.4969 M

Next, we need to determine the ratio between HCl and NaOH from the balanced equation. The ratio is 1:1, meaning that one mole of HCl reacts with one mole of NaOH.

So, the number of moles of HCl neutralized by NaOH is also equal to the number of moles of NaOH used in the titration:

Number of moles of HCl = Number of moles of NaOH

Substituting the value we found earlier:

Number of moles of HCl = 0.0213 L x 0.4969 M

Simply multiply the two values together to get the answer:

Number of moles of HCl = 0.01058497 moles

Therefore, approximately 0.0106 moles of HCl were neutralized by the NaOH.