This requires familiarity with the different theories (or concepts) of acids and bases.
On the Arrhenius concept, an acid is a substance that produces an H⁺ ion in water such that the H⁺ concentration increases, and a base is a substance that produces an OH⁻ ion in water such that the OH⁻ concentration increases.
On the Brønsted–Lowry concept, an acid is a substance that donates a proton (which is basically an H⁺ ion) in a solvent, and a base is a substance that accepts a proton in a solvent.
On the Lewis concept, an acid is a substance that accepts an electron pair in a solvent, and a base is a substance that donates an electron pair in a solvent.
The concepts become progressively broader, i.e., the Arrhenius concept is the most restrictive and the Lewis concept is the least restrictive. As a corollary, an Arrhenius acid or base is also both a Brønsted–Lowry acid or base and a Lewis acid or base, respectively; a Brønsted–Lowry acid or base is not necessarily an Arrhenius acid or base, but an Arrhenius acid or base is also a Lewis acid or base, respectively. And finally, a Lewis acid or base may not necessarily be either an Arrhenius or a Brønsted–Lowry acid or base.
So, with the above concepts in mind, we can match the statements in column A with the type of acid or base in column B:

Answer:- 2,1
Explanations:- Water is
and from it's formula it is clear that the ratio of H to O moles or atoms is 2:1 means two hydrogen atoms for each oxygen atom. No matter what amount of water we have, the ratio of H atoms to O atoms is always same.
Hence, the answer is 2,1.
Answer:
5.00 g of solute will remain undissolved at the bottom of the container
Explanation:
From the question, the solubility of the solute in the given solvent is 45.0 grams of solute per 500 grams of solvent.
Now if i pour 50.0 grams of solute into 800 grams of solvent, it means that only 45 g will dissolve in 500 g of solvent leaving the additional 5 g undissolved.
Hence, 5 g of solute will remain undissolved at the bottom of the container.
If the concentration of the hydrogen ions, increase then the solution would become more and more acidic and thus have a lower pH value than compared to the pH value before at the 1.0 X 10^-2 M.