How many milliliters of 0.20 M HCl are required to completely neutralize 50.0 mL of 0.80 M NaOH?

• A. 20 mL
• B. 100 mL
• C. 200 mL
• D. 400 mL

Answer: (C)

Verified step by step guidance

1. Write the balanced chemical equation for the neutralization reaction: \(\mathrm{HCl + NaOH \rightarrow NaCl + H_2O}\). This shows a 1:1 mole ratio between HCl and NaOH.
2. Calculate the moles of NaOH present using the formula: \(\text{moles} = M \times V\), where \(M\) is molarity and \(V\) is volume in liters. Convert 50.0 mL to liters before calculating.
3. Since the mole ratio of HCl to NaOH is 1:1, the moles of HCl required to neutralize the NaOH will be equal to the moles of NaOH calculated.
4. Use the moles of HCl and the molarity of the HCl solution (0.20 M) to find the volume of HCl needed using the formula: \(V = \frac{\text{moles}}{M}\). The volume will be in liters.
5. Convert the volume of HCl from liters to milliliters by multiplying by 1000 to get the final answer in milliliters.