Plz help me with this!

How does litmus paper indicate an acid?

Consider the point on the plot where 10.0 g of naoh have been added. what amount of naoh, in moles, has been added? 0.308 mol fecl3 initially present

Observation and experimentation have led many scientists to accept a theory about the origin of the universe. this theory is called the big bang theory. scientific evidence collected and observed by scientists around the world suggests that the universe is ever expanding from a hot and dense initial state. what makes this a scientific theory? (2 points)