Question

`Suppose you have a sample of NaOH (0.0315 L, to be exact). If this amount of NaOH is used to exactly titrate 0.0250 L of HCl that has a concentration of 0.105 M, what is the molarity of the NaOH? HINT: Remember to first get your balanced equation.

Answer 1

0.0835 M

Step-by-step explanation:

Step 1: Write the balanced equation

NaOH + HCl ⇒ NaCl + H₂O

Step 2: Calculate the reacting moles of HCl

0.0250 L of 0.105 M HCl react.

0.0250 L × 0.105 mol/L = 2.63 × 10⁻³ mol

Step 3: Calculate the reacting moles of NaOH

The molar ratio of NaOH to HCl is 1:1. The reacting moles of NaOH are 1/1 × 2.63 × 10⁻³ mol = 2.63 × 10⁻³ mol.

Step 4: Calculate the molarity of NaOH

2.63 × 10⁻³ moles of NaOH are in 0.0315 L of solution.

M = 2.63 × 10⁻³ mol / 0.0315 L = 0.0835 M