What is the change in ph when 0.025mole of NaOH is added to 1.00Lof pure water?

the answer is 5.4 but im not sure howWhat is the change in ph when 0.025mole of NaOH is added to 1.00Lof pure water?
pH of pure water = 7.00



NaOH is a strong base : NaOH = Na+ + OH-



[OH-]= 0.025 mol / 1.00 L = 0.025 M



pOH = - log 0.025 =1.60



pH = 14 - pOH = 14 - 1.60= 12.4



delta pH = 12.4 - 7.0 =5.4