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.
サイダー is a sweet, flavored carbonated soft drink, whereas ソーダ is the broader term covering plain soda water too.
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'.