How do metals oxide dissolved in water respond to litmus paper?

Q. A non-metal oxide was dissolved in water and then tested with both blue and red litmus papers. What will happen to the two litmus papers?

Q. Which substance when dissolved in water changes red litmus paper to blue.

Q. If vapours of dry ammonia gas are brought into contact with red litmus paper, what will happen to the colour of the litmus paper?

(a) Litmus paper turns blue
(b) Litmus paper turns pink
(c) No change in the litmus paper
(d) Litmus paper turns yellow

Q. Dry ammonia has no action on litmus paper, but a solution of ammonia in water turns red litmus paper blue. Why?