Acids And Bases

Acetic acid is a weaker acid than water, so in acetic acid, it is easier to distinguish between the strengths of HCl and HClO based on their ability to donate protons.

The for the conjugate base of carbonic acid is the equilibrium constant for the base dissociation of bicarbonate ions, which is given by the expression for the concentration of .

The conjugate base of a strong acid is the species formed when the acid donates a proton (H ).
For sulfuric acid (H SO ), the conjugate base is formed when one proton is lost, producing HSO .
This is the species that remains after H SO loses one proton.
Thus, the correct answer is (c).

When sulphur reacts with concentrated nitric acid (HNO ), it undergoes oxidation to produce sulfuric acid ( ), nitrogen dioxide ( ) and water ( ) as the products.
The reaction can be represented as follows:
Thus, the correct answer is (a).

Ammonium chloride (I) is the salt of a weak base (ammonium hydroxide) and a strong acid (hydrochloric acid). As a result, it dissociates in water to produce an acidic solution, which will have the lowest pH.

Ammonium ethanoate (II) is the salt of a weak acid (ethanoic acid) and a weak base (ammonium hydroxide). This salt will hydrolyze in water, but to a lesser extent than ammonium chloride, resulting in a more moderate pH compared to ammonium chloride.

Sodium ethanoate (III) is the salt of a strong base (sodium hydroxide) and a weak acid (ethanoic acid). This results in a basic solution because the sodium ion does not hydrolyze, while the ethanoate ion (acetate) can accept protons, making the solution more basic and leading to the highest pH.

Therefore, the correct order of pH is I < II < III.

The pH scale is logarithmic, meaning a change of 1 pH unit represents a tenfold change in acidity. The difference in pH between stomach acid (pH 2) and sour milk (pH 6) is 4 pH units. Therefore, stomach acid is 10 (or 10,000) times more acidic than sour milk. Thus, the correct answer is (d).

The percentage of empty space can be calculated by comparing the densities of solid and liquid argon. Using the formula for density and understanding the structure of fcc, the empty space is found to be 34.84\%.