Question

How many grams of NaOH are required to neutralize 25 mL of 0.1 M HCl solution?

• A. \( 0.1 \, \text{g} \)
• B. \( 0.5 \, \text{g} \)
• C. \( 1.0 \, \text{g} \)
• D. \( 2.0 \, \text{g} \)

Hint:

Remember: In a neutralization reaction, moles of acid = moles of base. Use this relationship to calculate the mass of the base required.

Answer 1

The Correct Option is A

Determine the Mass of NaOH for HCl Neutralization

Provided information:

• Volume of HCl solution: 25 mL (0.025 L)
• Molarity of HCl solution: 0.1 M
• Molar mass of NaOH: 40 g/mol

Step 1: Balanced Chemical Equation

Reaction: \[ \text{NaOH} + \text{HCl} \rightarrow \text{NaCl} + \text{H}_2\text{O} \] This indicates a 1:1 molar ratio between NaOH and HCl.

Step 2: Moles of HCl

Calculate moles of HCl: \[ \text{moles of HCl} = 0.1 \, \text{M} \times 0.025 \, \text{L} = 0.0025 \, \text{mol} \]

Step 3: Moles of NaOH Needed

Due to the 1:1 mole ratio, 0.0025 mol of NaOH is required.

Step 4: Mass of NaOH

Calculate the mass of NaOH: \[ \text{mass of NaOH} = 0.0025 \, \text{mol} \times 40 \, \text{g/mol} = 0.1 \, \text{g} \]

Summary:

To neutralize 25 mL of 0.1 M HCl, 0.1 grams of NaOH is necessary.