Calculate the mass of sodium hydroxide needed to make a 5.00L with a molarity of 0.400M​

Idon't understand what to put on the left lines i'm confused can anyone ?

In numbering carbon atoms in the parent chain of a hydrocarbon, why would you number from right to left, rather than left to right

You encounter a solution that is acidic and you decide to test it by adding a small amount of a strong acid. the ph lowers slightly but is approximately unchanged, and still remains acidic. what can you say about the solution? a. it is a buffer solution. b. it is not a buffer solution it is a strong acid solution. d. the solution has been neutralized. e. the solution has excess acid present