Why does the glass of water weigh less after the pill has dissolved? Why does the glass of water weigh less after the pill has dissolved? Nitrogen dioxide gas will be generated and released as the anti-acid pill dissolves. Water vapor will be generated and released as the anti-acid pill dissolves. Sulfur dioxide gas will be generated and released as the anti-acid pill dissolves. Carbon dioxide gas will be generated and released as the anti-acid pill dissolves?