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 
\(\text K_{ \text {sp}} [ \text {Fe(OH)}_3] = 2.6 \times 10^{-39}\)

1.	4.458 × 10–25 M	2.	3.458 × 10–25 M
3.	2.229 × 10–24 M	4.	4.458 × 10–22 M

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

At $25°\mathrm{C}$ the dissociation constant of a base, BOH is $1.0\times {10}^{-12}$, the concentration of hydroxyl ions 0.01 M aqueous solution of the base would become

1. $2.0\times {10}^{-6}<mspace\; width="1em"></mspace>\mathrm{mol}<mspace\; width="1em"></mspace>{\mathrm{L}}^{-1}$

2. $1.0\times {10}^{-5}<mspace\; width="1em"></mspace>\mathrm{mol}<mspace\; width="1em"></mspace>{\mathrm{L}}^{-1}$

3. $1.0\times {10}^{-6}<mspace\; width="1em"></mspace>\mathrm{mol}<mspace\; width="1em"></mspace>{\mathrm{L}}^{-1}$

4. $1.0\times {10}^{-7}<mspace\; width="1em"></mspace>\mathrm{mol}<mspace\; width="1em"></mspace>{\mathrm{L}}^{-1}$

Calculate the solubility of AgI in a 10⁻⁴ N KI solution at 25°C, given that the solubility product constant (Kₛₚ) of AgI
is 1.0 × 10⁻¹⁶ mol² L⁻².

1. $1.0\times {10}^{-10}$

2. $1.0\times {10}^{-12}$

3. $1.0\times {10}^{-16}$

4. $1.0\times {10}^{-8}$

When 0.1 mole of CH3NH2 (ionization constant ${\mathrm{K}}_{\mathrm{b}}=5\times {10}^{-4}$) is mixed with 0.08 mol HCl and the volume is made up of 1 litre. The [H+] of resulting solution is - (log 4 =  0.60)

1. \(8 \times10^{-11} M~\)
2. \(6 \times10^{-5} M~\)
$\mathrm{}$3. \(1.6 \times10^{-11} M~\)
4. \(8 \times10^{-2} ~M~ \)$\mathrm{}$

The solution with pH value close to 1.0 among the following is:

Given the following equilibrium reactions:

Ag⁺ + 2NH₃ ⇌ [Ag(NH₃)₂]⁺  K₁ = 1.8 × 10⁷

Ag⁺ + Cl⁻ ⇌ AgCl(s)  K₂ = 5.6 × 10⁹

Calculate the equilibrium constant for the reaction:

AgCl(s) + 2NH₃ ⇌ [Ag(NH₃)₂]⁺ + Cl⁻

Three sparingly soluble salts A₂X, AX, and AX₃ have the same solubility product. Their solubilities will be in the order:

1. AX₃>AX>A₂X

2. AX₃ < A₂X>AX

3. AX>AX₃>A₂X

4. AX>A₂X>AX₃

Find the solution(s) having a pH between 6 and 7.

I. 2 × 10⁻⁶ M NaOH
II. 2 × 10⁻⁶ M HCl
III. 10⁻⁸ M HCl
IV. 10⁻¹³ M NaOH