Question

What is a base?

Answer 1

Answer:   A. a substance that is alkaline

Explanation: Base is defined as the substance which is alkaline in nature.

It is the species which can accept a proton because of the lone pair of electrons or vacant orbitals present on them.

It is that species which donates its OH- ions to the solution (Arrhenius Base)

It is a substance which has a high pH value as low pH values belongs the the acidic species.

A species which can donate its H+ ion is known as Acidic species.

Answer 2

The correct answer is A
its not D because a low pH is a acid
its not C because a base releases OH- ions
its not B because it donates and releases OH- ions

hope this helps