What is the ionization constant ( K_a ) of water if its degree of ionization is 1.8 x 10^-9 ?

1. $1.8\times {10}^{-9}$

2. $1.8\times {10}^{-16}$

3. $1.8\times {10}^{-14}$

4. Cannot be calculated

The decreasing order of the acidic nature of H₂SO₄ (I), H₃PO₄ (II), and HClO₄ (III) is:${\mathrm{}}_{}$

1. I>II>III

2. I>III>II

3. III>I>II

4. III>II>I

The number of H⁺ ions present in 1 cm³ of a solution whose pH is 10 is:

The \(K_a\) values of formic acid and acetic acid are respectively $1.77\times {10}^{-4}$ and $1.75\times {10}^{-5}$. The ratio of the acid strength of 0.1 N acids is :

1. 0.1

2. 0.3

3. 3.178

4. 100

Why is ZnS not precipitated when H₂S is passed through an acidic medium,
whereas CuS is precipitated under the same conditions?

1. ${\mathrm{K}}_{\mathrm{sp}}<mspace\; width="1em"></mspace>\mathrm{CuS}<<{\mathrm{K}}_{\mathrm{sp}}<mspace\; width="1em"></mspace>\mathrm{ZnS}$

2.$<mspace\; width="1em"></mspace>{\mathrm{K}}_{\mathrm{sp}}<mspace\; width="1em"></mspace>\mathrm{CuS}>>{\mathrm{K}}_{\mathrm{sp}}<mspace\; width="1em"></mspace>\mathrm{ZnS}$

3. ${\mathrm{K}}_{\mathrm{sp}}<mspace\; width="1em"></mspace>\mathrm{CuS}={\mathrm{K}}_{\mathrm{sp}}<mspace\; width="1em"></mspace>\mathrm{ZnS}$

4. None of the above

Consider the following acids:

The correct order of strength is:
1. II>III>I>IV
2. IV>II>III>I
3. IV>III>II>I
4. III>II>IV>I

The hydrogen ion concentration is 0.2 M ethanoic acid $({\mathrm{K}}_{\mathrm{C}}=2\times {10}^{-5}<mspace\; width="1em"></mspace>\mathrm{mol}<mspace\; width="1em"></mspace>{\mathrm{dm}}^{-3})$ is approximately

1. ${10}^{-4}$

2. $2\times {10}^{-2}$

3. $2\times {10}^{-6}$

4. $2\times {10}^{-3}$

The pH of a solution made by mixing 50 mL of 0.01 M barium hydroxide solution with 50 mL of H₂O is

Find the molar solubility of Fe(OH)₃ in a buffer solution that is 0.10 M in NH₄Cl and 0.10 M in NH₃  :
\(\mathrm{K}_{\mathrm{b}}\left(\mathrm{NH}_3\right)=1.8 \times 10^{-5}\) and 
\(\text K_{ \text {sp}} [ \text {Fe(OH)}_3] = 2.6 \times 10^{-39}\)

A base dissolved in water yields a solution with a hydroxyl ion concentration of \(0.05 \mathrm{~mol}~ \mathrm{litre}^{-1}\). The solution is: