Question

You are titrating a solution of sodium hydroxide of unknown concentration with a solution of phosphoric acid that has a concentration of 0.220 M. Starting with 24.0 mL of the sodium hydroxide solution, you use 194 ml. of the acid to titrate the base to completion. Calculate the concentration of the sodium hydroxide solution

O 0.534 M
O 0.178 M
O 0.0093 M
O 0.356 M
O 0.272 M

Answer 1

The concentration of the sodium hydroxide solution is calculated by using the titration formula and adjusting for the 1:3 stoichiometry with phosphoric acid. The calculated concentration of sodium hydroxide is 0.534 M.

Step-by-step explanation:

To calculate the concentration of the sodium hydroxide solution, we use the titration formula:

nbase = nacid

Where n is the number of moles, which is calculated by multiplying concentration (C) by volume (V). Phosphoric acid has a reaction stoichiometry of 1:3 with sodium hydroxide, so we need to adjust the equation accordingly:

CNaOH × VNaOH = 3 × (CH3PO4 × VH3PO4)

Plugging in the values:

CNaOH × 0.0240 L = 3 × (0.220 M × 0.194 L)

Solving for CNaOH, we get:

CNaOH = (3 × 0.220 M × 0.194 L) / 0.0240 L

CNaOH = 0.534 M

Hence, the concentration of the sodium hydroxide solution is 0.534 M.