Scientifically, there are various definitions for acid, but to the person who is not familiar with chemistry it can only be explained by experiment.
A simple experiment of acid and baking soda can be performed here. Suppose you have a solution in your house and you need to check if it is acidic or not, just add it to some amount of baking soda, if bubbles are formed, it confirms the solution is acidic. In this way, one can help a person to identify an acidic solution who is not familiar with chemistry.
To the person who is familiar with chemistry, it can be explained as a solution that turns blue litmus paper red and in the pH meter, the pH value lies between 0 to 7. If the value is close to zero, the acid is strong and it is weak if the value is close to 7. Here the pH of given solution is 1.2 that means it is a strong acid.
