Question

The solid sodium hydroxide reacts with both CO2 [gas] and H20 [Liquid] while being weighed .
Q1 Where did the Carbon .dioxide and water come from

Answer 1

The CO2 and H2O come from air.
H2O as moisture in the air and CO2 a gas that found in air that released from human being.......

Answer 2

I agree with your answer but in fact the H2O in the air may well be vapor (gas), not liquid.

Answer 3

and probably is vapor.