soda
Refers to soda in general, including soda water, baking soda, or soda pop depending on context.
from Dutch
I want to drink a cold soda.
I mixed the whiskey with soda water and drank it.
Adding soda to lemonade gives it a nice fizz.
重曹 refers specifically to baking soda (sodium bicarbonate), one of the substances that ソーダ can loosely denote.
Standard katakana spelling for soda.
Ateji spelling; rarely used.
Borrowed from Dutch 'soda'.