Grade 11 : Chemistry - Equilibrium (Set 4)

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Grade 11 : Chemistry - Equilibrium (Set 4)— Questions & Detailed Solutions

Species Initial Concentration (M) Equilibrium Concentration (M)
$A(g)$ 1.0 0.6
$B(g)$ 1.0 0.6
$C(g)$ 0.0 0.8
For the reversible gaseous reaction $A(g) + B(g) \rightleftharpoons 2C(g)$ carried out in a 1.0 L closed vessel at constant temperature, the initial and equilibrium concentration data are recorded in the table above. What is the value of the equilibrium constant $K_c$?

Species	Initial Concentration (M)	Equilibrium Concentration (M)
$A(g)$	1.0	0.6
$B(g)$	1.0	0.6
$C(g)$	0.0	0.8

(A)

1.33

(B)

1.78

(C)

2.22

(D)

0.80

View Correct Answer & Detailed Solution

✓ Correct Option: (B)

Explanation: The equilibrium constant expression for $A(g) + B(g) \rightleftharpoons 2C(g)$ is $K_c = \frac{[C]^2}{[A][B]}$. Substituting the equilibrium concentrations: $K_c = \frac{(0.8)^2}{(0.6)(0.6)} = \frac{0.64}{0.36} = \frac{16}{9} \approx 1.78$.

Reaction Setup: A gas-phase reaction $2SO_2(g) + O_2(g) \rightleftharpoons 2SO_3(g)$ achieves equilibrium at $T = 300\text{ K}$. At this temperature, the concentration equilibrium constant $K_c$ is measured to be $82.0m^{-1}$. Take $R = 0.082\text{ L atm mol}^{-1}\text{K}^{-1}$.
What is the value of the pressure equilibrium constant $K_p$ (in $\text{atm}^{-1}$) at 300 K?

(A)

$3.33\text{ atm}^{-1}$

(B)

$2.00\text{ atm}^{-1}$

(C)

$4.10\text{ atm}^{-1}$

(D)

$1.50\text{ atm}^{-1}$

View Correct Answer & Detailed Solution

✓ Correct Option: (A)

Explanation: The relationship between $K_p$ and $K_c$ is $K_p = K_c (RT)^{\Delta n}$. Here, $\Delta n = 2 - (2 + 1) = -1$. $RT = 0.082 \times 300 = 24.6$. Thus, $K_p = 82.0 \times (24.6)^{-1} = \frac{82.0}{24.6} \approx 3.33\text{ atm}^{-1}$.

System Description:
Consider the Haber process synthesis of ammonia: $N_2(g) + 3H_2(g) \rightleftharpoons 2NH_3(g)$ with $\Delta H = -92\text{ kJ mol}^{-1}$.
According to Le Chatelier's principle, which change will shift the position of equilibrium toward the formation of more $NH_3(g)$?

(A)

Increasing the temperature at constant volume

(B)

Increasing the volume of the reaction container

(C)

Increasing the total pressure by reducing the container volume

(D)

Removing $N_2(g)$ from the reaction vessel

View Correct Answer & Detailed Solution

✓ Correct Option: (C)

Explanation: The forward reaction produces 2 moles of gas from 4 moles of reactants ($\Delta n < 0$). Increasing total pressure shifts equilibrium toward fewer gaseous moles (forward direction to form more $NH_3$).

Acid Ionization Constant ($K_a$)
Acid W $1.8 \times 10^{-4}$
Acid X $4.0 \times 10^{-5}$
Acid Y $1.0 \times 10^{-7}$
Acid Z $3.0 \times 10^{-9}$
Four monoprotic weak acids W, X, Y, and Z are prepared as separate 0.10 M aqueous solutions at $25^\circ\text{C}$. Based on their $K_a$ values in the table, which solution will have the highest pH?

Acid	Ionization Constant ($K_a$)
Acid W	$1.8 \times 10^{-4}$
Acid X	$4.0 \times 10^{-5}$
Acid Y	$1.0 \times 10^{-7}$
Acid Z	$3.0 \times 10^{-9}$

(A)

Solution W

(B)

Solution X

(C)

Solution Y

(D)

Solution Z

View Correct Answer & Detailed Solution

✓ Correct Option: (D)

Explanation: A smaller $K_a$ value indicates a weaker acid that dissociates less, producing a lower $[H^+]$ concentration. Lower $[H^+]$ corresponds to a higher pH. Acid Z has the smallest $K_a$ ($3.0 \times 10^{-9}$), so its solution has the highest pH.

Solution Preparation: A student prepares an aqueous solution by dissolving sulfuric acid $H_2SO_4$ to achieve a concentration of 0.0050 M. Assume complete ionization of both protons.
What is the pH of this $0.0050m H_2SO_4$ solution at $25^\circ\text{C}$?

(A)

2.00

(B)

2.30

(C)

1.70

(D)

3.00

View Correct Answer & Detailed Solution

✓ Correct Option: (A)

Explanation: Since $H_2SO_4$ is a diprotic strong acid, $[H^+] = 2 \times 0.0050m = 0.010m = 10^{-2}m$. Therefore, $pH = -\log_{10}(10^{-2}) = 2.00$.

Solubility Equilibria Setup:
Solid silver chloride $AgCl(s)$ has a solubility product constant $K_{sp} = 1.6 \times 10^{-10}$ at $25^\circ\text{C}$.
What is the molar solubility of AgCl in a 0.10 M solution of NaCl?

(A)

$1.26 \times 10^{-5}m$

(B)

$1.60 \times 10^{-9}m$

(C)

$1.60 \times 10^{-11}m$

(D)

$3.20 \times 10^{-9}m$

View Correct Answer & Detailed Solution

✓ Correct Option: (B)

Explanation: In $0.10m NaCl$, $[Cl^-] = 0.10m$ due to common ion effect. $K_{sp} = [Ag^+][Cl^-] \implies 1.6 \times 10^{-10} = s' \times 0.10 \implies s' = 1.6 \times 10^{-9}m$.

Buffer System Analysis: A acidic buffer solution is prepared by mixing 0.20 M acetic acid ($CH_3COOH$) and 0.20 M sodium acetate ($CH_3COONa$). The dissociation constant of acetic acid $K_a = 1.8 \times 10^{-5}$ ($pK_a = 4.74$).
What is the pH of this buffer solution?

(A)

3.74

(B)

5.74

(C)

4.74

(D)

7.00

View Correct Answer & Detailed Solution

✓ Correct Option: (C)

Explanation: Using the Henderson-Hasselbalch equation: $pH = pK_a + \log_{10}\left(\frac{[\text{Salt}]}{[\text{Acid}]}\right) = 4.74 + \log_{10}\left(\frac{0.20}{0.20}\right) = 4.74 + \log_{10}(1) = 4.74$.

[Reaction Vessel: A(g) + B(g) <==> C(g) + D(g)]
Given: Kc = 50.0 at 500 K.
Current state: [A] = 0.20 M, [B] = 0.20 M, [C] = 1.00 M, [D] = 1.00 M.
Calculate the reaction quotient $Q_c$ and determine the direction in which the reaction will proceed to establish equilibrium.

(A)

$Q_c = 25.0$; reaction proceeds in the forward direction

(B)

$Q_c = 25.0$; reaction proceeds in the reverse direction

(C)

$Q_c = 50.0$; system is already at equilibrium

(D)

$Q_c = 0.04$; reaction proceeds in the forward direction

View Correct Answer & Detailed Solution

✓ Correct Option: (A)

Explanation: $Q_c = \frac{[C][D]}{[A][B]} = \frac{(1.00)(1.00)}{(0.20)(0.20)} = \frac{1.00}{0.04} = 25.0$. Since $Q_c = 25.0 < K_c = 50.0$, the reaction will proceed in the forward direction to generate more products.

Heterogeneous Reaction: Calcium carbonate decomposes upon heating according to the equilibrium equation: $CaCO_3(s) \rightleftharpoons CaO(s) + CO_2(g)$.
Which of the following is the correct expression for the equilibrium constant $K_p$ for this heterogeneous system?

(A)

$K_p = \frac{P_{CaO} \cdot P_{CO_2}}{P_{CaCO_3}}$

(B)

$K_p = \frac{P_{CO_2}}{P_{CaCO_3}}$

(C)

$K_p = P_{CaO} \cdot P_{CO_2}$

(D)

$K_p = P_{CO_2}$

View Correct Answer & Detailed Solution

✓ Correct Option: (D)

Explanation: Pure solids ($CaCO_3$ and CaO) have unit activity and their concentrations/pressures do not appear in the equilibrium expression. Therefore, $K_p = P_{CO_2}$.

Q10

Temperature Effect Study: The reaction $N_2O_4(g) \rightleftharpoons 2NO_2(g)$ is endothermic ($\Delta H > 0$). At 298 K, the equilibrium constant is $K_1$. At 373 K, the equilibrium constant is $K_2$.
How do $K_1$ and $K_2$ compare, and what happens to the equilibrium concentration of $NO_2$ as temperature increases?

(A)

$K_2 < K_1$; $[NO_2]$ decreases

(B)

$K_2 > K_1$; $[NO_2]$ increases

(C)

$K_2 = K_1$; $[NO_2]$ remains constant

(D)

$K_2 > K_1$; $[NO_2]$ decreases

View Correct Answer & Detailed Solution

✓ Correct Option: (B)

Explanation: For an endothermic reaction ($\Delta H > 0$), increasing temperature increases the value of the equilibrium constant ($K_2 > K_1$). As $K$ increases, the equilibrium shifts forward, increasing $[NO_2]$.

Q11

Salt Solubility Expression: Consider a sparingly soluble salt of formula $A_2B_3$ dissolving in water to reach saturation: $A_2B_3(s) \rightleftharpoons 2A^{3+}(aq) + 3B^{2-}(aq)$.
If the molar solubility of $A_2B_3$ is $s\text{ mol L}^{-1}$, what is the correct expression for its solubility product constant $K_{sp}$?

(A)

$K_{sp} = 6s^5$

(B)

$K_{sp} = 36s^5$

(C)

$K_{sp} = 108s^5$

(D)

$K_{sp} = 254s^5$

View Correct Answer & Detailed Solution

✓ Correct Option: (C)

Explanation: At equilibrium, $[A^{3+}] = 2s$ and $[B^{2-}] = 3s$. $K_{sp} = [A^{3+}]^2 [B^{2-}]^3 = (2s)^2 (3s)^3 = 4s^2 \cdot 27s^3 = 108s^5$.

Q12

High Temperature Water Autoionization: At an elevated temperature of $90^\circ\text{C}$ (363 K), the ionic product of pure water $K_w$ increases to $1.0 \times 10^{-13}$.
What is the pH of pure neutral water at $90^\circ\text{C}$?

(A)

6.50

(B)

7.00

(C)

7.50

(D)

6.00

View Correct Answer & Detailed Solution

✓ Correct Option: (A)

Explanation: For neutral water, $[H^+] = [OH^-] = \sqrt{K_w} = \sqrt{1.0 \times 10^{-13}} = 10^{-6.5}m$. Thus $pH = -\log_{10}(10^{-6.5}) = 6.50$. Note that water remains neutral because $[H^+] = [OH^-]$.

Q13

Statement I: $NH_3$ acts as a Lewis base in reaction with $BF_3$.
Statement II: $NH_3$ donates an unshared pair of electrons to form a coordinate covalent bond with $BF_3$.
Evaluate Statements I and II based on acid-base concepts.

(A)

Both statements are correct, and Statement II is the correct explanation for Statement I.

(B)

Both statements are correct, but Statement II is NOT the correct explanation for Statement I.

(C)

Statement I is correct, but Statement II is incorrect.

(D)

Statement I is incorrect, but Statement II is correct.

View Correct Answer & Detailed Solution

✓ Correct Option: (A)

Explanation: According to the Lewis acid-base theory, an electron pair donor is a Lewis base. $NH_3$ has a lone pair of electrons on nitrogen which it donates to electron-deficient $BF_3$, so both statements are correct and linked.

Q14

Degree of Ionization: A weak acid HA has an ionization constant $K_a = 1.0 \times 10^{-5}$. A solution of this acid is prepared at concentration $C = 0.10m$.
What is the degree of ionization ($\alpha$) of the weak acid in this solution?

(A)

0.001

(B)

0.050

(C)

0.010

(D)

0.100

View Correct Answer & Detailed Solution

✓ Correct Option: (C)

Explanation: Using Ostwald's Dilution Law for weak electrolytes: $\alpha = \sqrt{\frac{K_a}{C}} = \sqrt{\frac{1.0 \times 10^{-5}}{0.10}} = \sqrt{1.0 \times 10^{-4}} = 0.010$ (or 1%).

Q15

Inert Gas Addition System:
The equilibrium system $PCl_5(g) \rightleftharpoons PCl_3(g) + Cl_2(g)$ is maintained inside a rigid container at constant volume and temperature.
What is the effect of adding an inert gas (such as Argon) to this system at constant volume?

(A)

The equilibrium shifts toward products

(B)

The position of equilibrium remains unaffected

(C)

The equilibrium shifts toward reactants

(D)

$K_p$ value increases

View Correct Answer & Detailed Solution

✓ Correct Option: (B)

Explanation: Adding an inert gas at constant volume increases the total pressure, but does not alter the partial pressures or concentrations of reactants or products. Hence, the equilibrium position remains unchanged.

Q16

Precipitation Test: Equal volumes of $2.0 \times 10^{-4}m Ba(NO_3)_2$ solution and $2.0 \times 10^{-4}m Na_2SO_4$ solution are mixed together. The $K_{sp}$ of $BaSO_4$ is $1.1 \times 10^{-10}$.
Will a precipitate of $BaSO_4$ form upon mixing?

(A)

Yes, because $Q_{sp} = 1.0 \times 10^{-8} > K_{sp}$

(B)

No, because $Q_{sp} = 1.0 \times 10^{-8} < K_{sp}$

(C)

No, because $Q_{sp} = 4.0 \times 10^{-8} = K_{sp}$

(D)

Yes, because $Q_{sp} = 2.0 \times 10^{-4} > K_{sp}$

View Correct Answer & Detailed Solution

✓ Correct Option: (A)

Explanation: Upon mixing equal volumes, concentrations are halved: $[Ba^{2+}] = 1.0 \times 10^{-4}m$ and $[SO_4^{2-}] = 1.0 \times 10^{-4}m$. Ionic product $Q_{sp} = (1.0 \times 10^{-4})(1.0 \times 10^{-4}) = 1.0 \times 10^{-8}$. Since $Q_{sp} > K_{sp}$, precipitation occurs.

Q17

Indicator pH Range of Color Change Acid Color Base Color
Methyl Orange $3.1 - 4.4$ Red Yellow
Bromothymol Blue $6.0 - 7.6$ Yellow Blue
Phenolphthalein $8.3 - 10.0$ Colorless Pink
During the titration of a strong acid (HCl) with a weak base ($NH_4OH$), the equivalence point pH is around 5.2. Based on the table, which indicator is most suitable for detecting the equivalence point?

Indicator	pH Range of Color Change	Acid Color	Base Color
Methyl Orange	$3.1 - 4.4$	Red	Yellow
Bromothymol Blue	$6.0 - 7.6$	Yellow	Blue
Phenolphthalein	$8.3 - 10.0$	Colorless	Pink

(A)

Phenolphthalein

(B)

Bromothymol Blue

(C)

Universal Indicator

(D)

Methyl Orange

View Correct Answer & Detailed Solution

✓ Correct Option: (D)

Explanation: For strong acid - weak base titrations, the equivalence point lies in the acidic pH range ($4-6$). Methyl Orange changes color sharply in the pH range $3.1 - 4.4$, making it suitable for this titration.

Q18

Chemical Species Formula
Bicarbonate ion $HCO_3^-$
Sulfate ion $SO_4^{2-}$
Ammonium ion $NH_4^+$
Nitrate ion $NO_3^-$
Which species in the table is amphiprotic according to Bronsted-Lowry theory (can act as both an acid and a base)?

Chemical Species	Formula
Bicarbonate ion	$HCO_3^-$
Sulfate ion	$SO_4^{2-}$
Ammonium ion	$NH_4^+$
Nitrate ion	$NO_3^-$

(A)

$HCO_3^-$

(B)

$SO_4^{2-}$

(C)

$NH_4^+$

(D)

$NO_3^-$

View Correct Answer & Detailed Solution

✓ Correct Option: (A)

Explanation: $HCO_3^-$ can donate a proton to form $CO_3^{2-}$ (acting as acid) or accept a proton to form $H_2CO_3$ (acting as base). Thus, it is amphiprotic.

Q19

Thermodynamic Relation: For a general reversible reaction at $T = 300\text{ K}$, the equilibrium constant $K_c = 100$. Take $R = 8.314\text{ J K}^{-1}\text{ mol}^{-1}$ and $2.303 \times R \times T \approx 5744\text{ J mol}^{-1} = 5.744\text{ kJ mol}^{-1}$.
What is the standard Gibbs free energy change $\Delta G^\circ$ for this reaction?

(A)

$+11.49\text{ kJ mol}^{-1}$

(B)

$-5.74\text{ kJ mol}^{-1}$

(C)

$-11.49\text{ kJ mol}^{-1}$

(D)

$+5.74\text{ kJ mol}^{-1}$

View Correct Answer & Detailed Solution

✓ Correct Option: (C)

Explanation: The thermodynamic formula is $\Delta G^\circ = -2.303 RT \log_{10} K$. Substituting values: $\Delta G^\circ = -5.744 \times \log_{10}(100) = -5.744 \times 2 = -11.49\text{ kJ mol}^{-1}$.

Q20

Salt Hydrolysis Problem: Ammonium chloride ($NH_4Cl$) is a salt formed from a strong acid (HCl) and a weak base ($NH_4OH$).
Which type of hydrolysis occurs in an aqueous solution of $NH_4Cl$, and what is the nature of the solution?

(A)

Anionic hydrolysis; basic solution ($pH > 7$)

(B)

Cationic hydrolysis; acidic solution ($pH < 7$)

(C)

Both cationic and anionic hydrolysis; neutral solution ($pH = 7$)

(D)

No hydrolysis; neutral solution ($pH = 7$)

View Correct Answer & Detailed Solution

✓ Correct Option: (B)

Explanation: $NH_4Cl$ dissociates into $NH_4^+$ and $Cl^-$. The cation $NH_4^+$ reacts with water: $NH_4^+ + H_2O \rightleftharpoons NH_4OH + H^+$. This cationic hydrolysis generates excess $H^+$ ions, yielding an acidic solution ($pH < 7$).

Grade 11 : Chemistry - Equilibrium (Set 4)

Grade 11 : Chemistry - Equilibrium (Set 4)— Questions & Detailed Solutions

System Description:
Consider the Haber process synthesis of ammonia: $N_2(g) + 3H_2(g) \rightleftharpoons 2NH_3(g)$ with $\Delta H = -92\text{ kJ mol}^{-1}$.
According to Le Chatelier's principle, which change will shift the position of equilibrium toward the formation of more $NH_3(g)$?

Solution Preparation: A student prepares an aqueous solution by dissolving sulfuric acid $H_2SO_4$ to achieve a concentration of 0.0050 M. Assume complete ionization of both protons.
What is the pH of this $0.0050m H_2SO_4$ solution at $25^\circ\text{C}$?

Solubility Equilibria Setup:
Solid silver chloride $AgCl(s)$ has a solubility product constant $K_{sp} = 1.6 \times 10^{-10}$ at $25^\circ\text{C}$.
What is the molar solubility of AgCl in a 0.10 M solution of NaCl?

Buffer System Analysis: A acidic buffer solution is prepared by mixing 0.20 M acetic acid ($CH_3COOH$) and 0.20 M sodium acetate ($CH_3COONa$). The dissociation constant of acetic acid $K_a = 1.8 \times 10^{-5}$ ($pK_a = 4.74$).
What is the pH of this buffer solution?

[Reaction Vessel: A(g) + B(g) <==> C(g) + D(g)]
Given: Kc = 50.0 at 500 K.
Current state: [A] = 0.20 M, [B] = 0.20 M, [C] = 1.00 M, [D] = 1.00 M.
Calculate the reaction quotient $Q_c$ and determine the direction in which the reaction will proceed to establish equilibrium.

Heterogeneous Reaction: Calcium carbonate decomposes upon heating according to the equilibrium equation: $CaCO_3(s) \rightleftharpoons CaO(s) + CO_2(g)$.
Which of the following is the correct expression for the equilibrium constant $K_p$ for this heterogeneous system?

High Temperature Water Autoionization: At an elevated temperature of $90^\circ\text{C}$ (363 K), the ionic product of pure water $K_w$ increases to $1.0 \times 10^{-13}$.
What is the pH of pure neutral water at $90^\circ\text{C}$?

Statement I: $NH_3$ acts as a Lewis base in reaction with $BF_3$.
Statement II: $NH_3$ donates an unshared pair of electrons to form a coordinate covalent bond with $BF_3$.
Evaluate Statements I and II based on acid-base concepts.

Degree of Ionization: A weak acid HA has an ionization constant $K_a = 1.0 \times 10^{-5}$. A solution of this acid is prepared at concentration $C = 0.10m$.
What is the degree of ionization ($\alpha$) of the weak acid in this solution?

Inert Gas Addition System:
The equilibrium system $PCl_5(g) \rightleftharpoons PCl_3(g) + Cl_2(g)$ is maintained inside a rigid container at constant volume and temperature.
What is the effect of adding an inert gas (such as Argon) to this system at constant volume?

Precipitation Test: Equal volumes of $2.0 \times 10^{-4}m Ba(NO_3)_2$ solution and $2.0 \times 10^{-4}m Na_2SO_4$ solution are mixed together. The $K_{sp}$ of $BaSO_4$ is $1.1 \times 10^{-10}$.
Will a precipitate of $BaSO_4$ form upon mixing?

Chemical Species Formula
Bicarbonate ion $HCO_3^-$
Sulfate ion $SO_4^{2-}$
Ammonium ion $NH_4^+$
Nitrate ion $NO_3^-$
Which species in the table is amphiprotic according to Bronsted-Lowry theory (can act as both an acid and a base)?

Salt Hydrolysis Problem: Ammonium chloride ($NH_4Cl$) is a salt formed from a strong acid (HCl) and a weak base ($NH_4OH$).
Which type of hydrolysis occurs in an aqueous solution of $NH_4Cl$, and what is the nature of the solution?

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Grade 11 : Chemistry - Equilibrium (Set 4)

Grade 11 : Chemistry - Equilibrium (Set 4)— Questions & Detailed Solutions

System Description:Consider the Haber process synthesis of ammonia: $N_2(g) + 3H_2(g) \rightleftharpoons 2NH_3(g)$ with $\Delta H = -92\text{ kJ mol}^{-1}$.According to Le Chatelier's principle, which change will shift the position of equilibrium toward the formation of more $NH_3(g)$?

Solution Preparation: A student prepares an aqueous solution by dissolving sulfuric acid $H_2SO_4$ to achieve a concentration of 0.0050 M. Assume complete ionization of both protons.What is the pH of this $0.0050m H_2SO_4$ solution at $25^\circ\text{C}$?

Solubility Equilibria Setup:Solid silver chloride $AgCl(s)$ has a solubility product constant $K_{sp} = 1.6 \times 10^{-10}$ at $25^\circ\text{C}$.What is the molar solubility of AgCl in a 0.10 M solution of NaCl?

Buffer System Analysis: A acidic buffer solution is prepared by mixing 0.20 M acetic acid ($CH_3COOH$) and 0.20 M sodium acetate ($CH_3COONa$). The dissociation constant of acetic acid $K_a = 1.8 \times 10^{-5}$ ($pK_a = 4.74$).What is the pH of this buffer solution?

[Reaction Vessel: A(g) + B(g) <==> C(g) + D(g)]Given: Kc = 50.0 at 500 K.Current state: [A] = 0.20 M, [B] = 0.20 M, [C] = 1.00 M, [D] = 1.00 M.Calculate the reaction quotient $Q_c$ and determine the direction in which the reaction will proceed to establish equilibrium.

Heterogeneous Reaction: Calcium carbonate decomposes upon heating according to the equilibrium equation: $CaCO_3(s) \rightleftharpoons CaO(s) + CO_2(g)$.Which of the following is the correct expression for the equilibrium constant $K_p$ for this heterogeneous system?

High Temperature Water Autoionization: At an elevated temperature of $90^\circ\text{C}$ (363 K), the ionic product of pure water $K_w$ increases to $1.0 \times 10^{-13}$.What is the pH of pure neutral water at $90^\circ\text{C}$?

Statement I: $NH_3$ acts as a Lewis base in reaction with $BF_3$.Statement II: $NH_3$ donates an unshared pair of electrons to form a coordinate covalent bond with $BF_3$.Evaluate Statements I and II based on acid-base concepts.

Degree of Ionization: A weak acid HA has an ionization constant $K_a = 1.0 \times 10^{-5}$. A solution of this acid is prepared at concentration $C = 0.10m$.What is the degree of ionization ($\alpha$) of the weak acid in this solution?

Inert Gas Addition System:The equilibrium system $PCl_5(g) \rightleftharpoons PCl_3(g) + Cl_2(g)$ is maintained inside a rigid container at constant volume and temperature.What is the effect of adding an inert gas (such as Argon) to this system at constant volume?

Precipitation Test: Equal volumes of $2.0 \times 10^{-4}m Ba(NO_3)_2$ solution and $2.0 \times 10^{-4}m Na_2SO_4$ solution are mixed together. The $K_{sp}$ of $BaSO_4$ is $1.1 \times 10^{-10}$.Will a precipitate of $BaSO_4$ form upon mixing?

Chemical SpeciesFormulaBicarbonate ion$HCO_3^-$Sulfate ion$SO_4^{2-}$Ammonium ion$NH_4^+$Nitrate ion$NO_3^-$Which species in the table is amphiprotic according to Bronsted-Lowry theory (can act as both an acid and a base)?

Salt Hydrolysis Problem: Ammonium chloride ($NH_4Cl$) is a salt formed from a strong acid (HCl) and a weak base ($NH_4OH$).Which type of hydrolysis occurs in an aqueous solution of $NH_4Cl$, and what is the nature of the solution?

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System Description:
Consider the Haber process synthesis of ammonia: $N_2(g) + 3H_2(g) \rightleftharpoons 2NH_3(g)$ with $\Delta H = -92\text{ kJ mol}^{-1}$.
According to Le Chatelier's principle, which change will shift the position of equilibrium toward the formation of more $NH_3(g)$?

Solution Preparation: A student prepares an aqueous solution by dissolving sulfuric acid $H_2SO_4$ to achieve a concentration of 0.0050 M. Assume complete ionization of both protons.
What is the pH of this $0.0050m H_2SO_4$ solution at $25^\circ\text{C}$?

Solubility Equilibria Setup:
Solid silver chloride $AgCl(s)$ has a solubility product constant $K_{sp} = 1.6 \times 10^{-10}$ at $25^\circ\text{C}$.
What is the molar solubility of AgCl in a 0.10 M solution of NaCl?

Buffer System Analysis: A acidic buffer solution is prepared by mixing 0.20 M acetic acid ($CH_3COOH$) and 0.20 M sodium acetate ($CH_3COONa$). The dissociation constant of acetic acid $K_a = 1.8 \times 10^{-5}$ ($pK_a = 4.74$).
What is the pH of this buffer solution?

[Reaction Vessel: A(g) + B(g) <==> C(g) + D(g)]
Given: Kc = 50.0 at 500 K.
Current state: [A] = 0.20 M, [B] = 0.20 M, [C] = 1.00 M, [D] = 1.00 M.
Calculate the reaction quotient $Q_c$ and determine the direction in which the reaction will proceed to establish equilibrium.

Heterogeneous Reaction: Calcium carbonate decomposes upon heating according to the equilibrium equation: $CaCO_3(s) \rightleftharpoons CaO(s) + CO_2(g)$.
Which of the following is the correct expression for the equilibrium constant $K_p$ for this heterogeneous system?

High Temperature Water Autoionization: At an elevated temperature of $90^\circ\text{C}$ (363 K), the ionic product of pure water $K_w$ increases to $1.0 \times 10^{-13}$.
What is the pH of pure neutral water at $90^\circ\text{C}$?

Statement I: $NH_3$ acts as a Lewis base in reaction with $BF_3$.
Statement II: $NH_3$ donates an unshared pair of electrons to form a coordinate covalent bond with $BF_3$.
Evaluate Statements I and II based on acid-base concepts.

Degree of Ionization: A weak acid HA has an ionization constant $K_a = 1.0 \times 10^{-5}$. A solution of this acid is prepared at concentration $C = 0.10m$.
What is the degree of ionization ($\alpha$) of the weak acid in this solution?

Inert Gas Addition System:
The equilibrium system $PCl_5(g) \rightleftharpoons PCl_3(g) + Cl_2(g)$ is maintained inside a rigid container at constant volume and temperature.
What is the effect of adding an inert gas (such as Argon) to this system at constant volume?

Precipitation Test: Equal volumes of $2.0 \times 10^{-4}m Ba(NO_3)_2$ solution and $2.0 \times 10^{-4}m Na_2SO_4$ solution are mixed together. The $K_{sp}$ of $BaSO_4$ is $1.1 \times 10^{-10}$.
Will a precipitate of $BaSO_4$ form upon mixing?

Chemical Species Formula
Bicarbonate ion $HCO_3^-$
Sulfate ion $SO_4^{2-}$
Ammonium ion $NH_4^+$
Nitrate ion $NO_3^-$
Which species in the table is amphiprotic according to Bronsted-Lowry theory (can act as both an acid and a base)?

Salt Hydrolysis Problem: Ammonium chloride ($NH_4Cl$) is a salt formed from a strong acid (HCl) and a weak base ($NH_4OH$).
Which type of hydrolysis occurs in an aqueous solution of $NH_4Cl$, and what is the nature of the solution?