It is much better to use baking soda. Any acid that reacts with baking soda gives off carbon dioxide. Hence, you can see an endpoint through the fizzing. With this, you will know when to stop adding. If you use NaOH, you might add it to an acid that creates an exothermic reaction. For example, if the acid was sulfuric acid, it will create more heat which will lead to more unfortunate events. To be safe, you add baking soda to neutralize, then mix it with a bit of water.
