Suggestion: review freshman chem.(posted 8359 days ago)Even though sodium ion and hydroxide ion are stable, I wouldn't make too much solution especially if frequent bottle opening is expected, concentration is rather low, or stable pH is required.
There are some CO2 available in air, which is easy to dissolve in alkaline solutions. The result will be in loss of OH ions because CO2(g) + water produces protone and this protone and OH- form water. Thus H+ is removed from one side of CO2 equation and therefore CO2 is extremely readily soluble into hydroxide solution. Sodium hydroxide is a strong base, near 100% dissociation and pH is not buffered at all.