100 mL of an NaOH solution is neutralized by 50 mL of a 0.5M HCl solution. What is the molarity of the NaOH solution?

I don't knw

answer : a model is often used to explain and make things easier to understand when any scientific topic needs to be demonstrated and explained.

as in this case where a scientist wants to use a model to present the results of his detailed scientific investigation. he should do it as it will him to make the audience understand the concept in a much better way. also, it can be changed according to new scientific understandings.