PH Answer/definition - A value from 0 to 14 that is used to specify how acidic or basically a compound of when it is dissolved in water.
Ions Answer/definition - An atom or molecule that has a positive of negative charge.
Acid Answer/definition - A compound that increases the hydroxide ions (OH-) when it is dissolved in a solution. (Arrhenius Acid)
Base Answer/definition - A compound that increases hydrogen ions (H+) when it is dissolved in a solution.
Hope this helps you out :)))
The correct answer is d) methane (

)
The other options are elements.
Answer: compound
Explanation:
Element is a pure substance which is composed of atoms of similar elements.It can not be decomposed into simpler constituents using chemical reactions.Example: Copper
Compound is a pure substance which is made from atoms of different elements combined together in a fixed ratio by mass.It can be decomposed into simpler constituents using chemical reactions. Example: water
Mixture is a substance which has two or more components which do not combine chemically and do not have any fixed ratio in which they are present. Example: Air
Answer:
i need help with that too.
Explanation: