John was working on a Chemical Mixture whose weight comprise 90% liquid and 10% solid. The total weight of the mixture is 20 pounds. After a while, John noticed that some of the liquid evaporated and now the liquid comprises just 50% of the weight.
I am a word that begins with the letter “i.†If you add the letter “a†to me, I become a new word with a different meaning, but that sounds exactly the same. What word am I?