The formula for calculating concentration is C = m/v where C means concentration , M means moles in the solution , this time it’s sodium hydroxide and V means volume.
Day 1)
Volume = 22.80
Mole = 39.997
Day 1 concentration = 39.997 / 22.80
Day 1 answer = 1.754
Day 2)
The mole does not change but the volume does and for day 2 it is 23.20
Day 2 concentration = 39.997 / 23.20
Day 2 answer = 1.724
Day 3)
Day 3 concentration = 39.997 / 23.90
Day 3 answer = 1.674
Day 4)
Day 4 concentration = 39.997 / 24.75
Day 4 answer = 1.616
Day 5)
Day 5 concentration = 39.997 / 25.1
Day 5 answer = 1.594