How many moles of NaOH would you need to add to 800 ml of a 0.4 M H2CO3
solution in order to bring the pH of the solution to 10.5?
To determine the amount of NaOH needed to bring the pH of the solution to 10.5, we need to consider the reaction between NaOH and H2CO3, as well as the stoichiometry of the reaction.
First, let's write the balanced equation for the reaction between NaOH and H2CO3:
H2CO3 + 2NaOH → Na2CO3 + 2H2O
From the balanced equation, we can see that 1 mole of H2CO3 reacts with 2 moles of NaOH.
Given that the H2CO3 solution has a concentration of 0.4 M, we can calculate the number of moles of H2CO3 in the solution:
moles of H2CO3 = concentration of H2CO3 × volume of solution = 0.4 M × 0.8 L = 0.32 moles
Since 1 mole of H2CO3 reacts with 2 moles of NaOH, we can determine the number of moles of NaOH required using the mole ratio:
moles of NaOH = (moles of H2CO3 × 2) = 0.32 moles × 2 = 0.64 moles
Therefore, you would need to add 0.64 moles of NaOH to the solution in order to bring the pH to 10.5.