Each mole of NaOH releases one mole of Na+ ions and one mole of OH- ions.
Each mole of a substance contains 6.02 x 10²³ particles
Moles of NaOH = concentration x volume
Moles of NaOH = 0.4 x 1 = 0.4
Moles of Na+ = 0.4
Ions of Na+ = 6.02 x 10²³ x 0.4 = 2.41 x 10²³
Moles of OH- = 0.4
Ions of OH- = 6.02 x 10²³ x 0.4 = 2.41 x 10²³