Answer:
0.393 mol/L. 
Explanation:
The following data were obtained from the question:
Number of mole of NaOH = 0.550 mol
Volume of solution = 1.40 L
Molarity of NaOH =.? 
Molarity of a solution is simply defined as the mole of solute per unit litre of the solution. Mathematically, it is expressed as:
Molarity = mole /Volume 
With the above formula, we can obtain the molarity of the NaOH solution as follow:
Number of mole of NaOH = 0.550 mol
Volume of solution = 1.40 L
Molarity of NaOH =.? 
Molarity = mole / Volume 
Molarity of NaOH = 0.55 / 1.4
Molarity of NaOH = 0.393 mol/L 
Thus, the molarity of the NaOH solution is 0.393 mol/L.