Plz tell Q. B

Dear student
1. The baby wants to talk.
   Infinitive- to talk.
   This infinitive acts as a noun as it is clearly the object of the sentence.
2. To give generously is the best thing one can do.
   Infinitive- to give
  This infinitive acts as a noun as it is the subject of the sentence.
3. I need something to eat right now.
  Infinitive- to eat
  This infinitive acts as an adjective as it qualifies the noun 'something'.
4. I must eat something right now.
Infinitive- eat
This infinitive acts as a noun as it is the object of the sentence.
Regards