soda
Refers to soda in general, including soda water, baking soda, or soda pop depending on context.
from Dutch
冷たいソーダが飲みたい。
I want to drink a cold soda.
I mixed the whiskey with soda water and drank it.
レモネードにソーダを入れると炭酸が効いて美味しい。
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'.