Question

How much NaOH (grams) is needed to prepare 546mL of solution with a ph of 10.00?

Answer 1

pH 10 means pOH is 4. pOH of 4 means the concentration of thehydroxide is 1x10^-4 M.Since NaOH is a strong base, the concentration of the saltwill be the same!amount in mol = vol x concentration0.546 L ( 1x10^-4 M ) = 0.0000546 molmolar mass of NaOH is 40 g/mol(40.0 g/mol)(0.0000546 mol) = 0.002184 g ~ 0.0022 g NaOH

Answer 2

pH +pOH = 14
pOH = -log[OH-]
pOH = 14- pH = 4

[OH-] =10^-4 M

moles OH- = moles NaOH (b/c strong base dissociates completely)
moles OH- = 0.546 L ( 1e -4 M ) = 5.46 e-5 molMW =39.9971 g/mol
39.9971g/mol * 5.46 e-5 mol = 2.18 e-3 grams = 0.00218grams