NEET Equilibrium — Set 1

Question 1

For $ \ce{CO(g) + H2O(g) <=> CO2(g) + H2(g)} $, $ K_c = 1.6 $ at 700 K. If 0.5 mol $ \ce{CO} $ and 0.5 mol $ \ce{H2O} $ are in a 2 L vessel, what is $ [\ce{CO2}] $ at equilibrium?

Accepted Answer

Initial: $ [\ce{CO}] = [\ce{H2O}] = \frac{0.5}{2} = 0.25 \, \text{M} $, $ [\ce{CO2}] = [\ce{H2}] = 0 $. Let $ x = [\ce{CO2}] = [\ce{H2}] $, $ [\ce{CO}] = [\ce{H2O}] = 0.25 - x $. $ K_c = \frac{[\ce{CO2}][\ce{H2}]}{[\ce{CO}][\ce{H2O}]} = \frac{x^2}{(0.25 - x)^2} = 1.6 $, $ \frac{x}{0.25 - x} = \sqrt{1.6} \approx 1.265 $, $ x = 0.316 - 1.265x $, $ 2.265x = 0.316 $, $ x \approx 0.14 \, \text{M} $.

Question 2

For the reaction $ \ce{A(g) + B(g) <=> 2C(g)} $, if the equilibrium concentrations are $ [\ce{A}] = 0.1 \, \text{M} $, $ [\ce{B}] = 0.2 \, \text{M} $, and $ [\ce{C}] = 0.4 \, \text{M} $, what is the value of $ K_c $?

Accepted Answer

$ K_c = \frac{[\ce{C}]^2}{[\ce{A}][\ce{B}]} = \frac{(0.4)^2}{(0.1)(0.2)} = \frac{0.16}{0.02} = 8 $.

Question 3

For $ \ce{2SO3(g) <=> 2SO2(g) + O2(g)} $, $ K_c = 0.02 $ at 700 K. If 0.4 mol $ \ce{SO3} $ is in a 2 L vessel, what is $ [\ce{O2}] $ at equilibrium?

Accepted Answer

Initial: $ [\ce{SO3}] = 0.2 \, \text{M} $, $ [\ce{SO2}] = [\ce{O2}] = 0 $. Let $ x = [\ce{O2}] $, $ [\ce{SO2}] = 2x $, $ [\ce{SO3}] = 0.2 - 2x $. $ K_c = \frac{[\ce{SO2}]^2[\ce{O2}]}{[\ce{SO3}]^2} = \frac{(2x)^2 x}{(0.2 - 2x)^2} = 0.02 $, $ 4x^3 = 0.02 (0.04 - 0.8x + 4x^2) $, $ x \approx 0.016 \, \text{M} $.

NEET Chemistry: Equilibrium — Practice Set 1

Q1. For \( \ce{CO(g) + H2O(g) <=> CO2(g) + H2(g)} \), \( K_c = 1.6 \) at 700 K. If 0.5 mol \( \ce{CO} \) and 0.5 mol \( \ce{H2O} \) are in a 2 L vessel, what is \( [\ce{CO2}] \) at equilibrium?

Q2. For the reaction \( \ce{A(g) + B(g) <=> 2C(g)} \), if the equilibrium concentrations are \( [\ce{A}] = 0.1 \, \text{M} \), \( [\ce{B}] = 0.2 \, \text{M} \), and \( [\ce{C}] = 0.4 \, \text{M} \), what is the value of \( K_c \)?

Q3. For \( \ce{2SO3(g) <=> 2SO2(g) + O2(g)} \), \( K_c = 0.02 \) at 700 K. If 0.4 mol \( \ce{SO3} \) is in a 2 L vessel, what is \( [\ce{O2}] \) at equilibrium?

Q4. For \( \ce{2A(g) + B(g) <=> 2C(g)} \), if \( K_c = 16 \) and \( [\ce{A}] = 0.2 \, \text{M} \), \( [\ce{B}] = 0.1 \, \text{M} \) at equilibrium, what is \( [\ce{C}] \)?

Q5. For the equilibrium \( \ce{N2(g) + 3H2(g) <=> 2NH3(g)} \), if \( K_c = 16 \) at a certain temperature, what is \( K_c \) for the reverse reaction \( \ce{2NH3(g) <=> N2(g) + 3H2(g)} \)?

Q6. A weak acid \( \ce{HZ} \) (\( K_a = 3.2 \times 10^{-5} \)) is mixed with 0.02 M \( \ce{NaOH} \) in a 3:1 volume ratio (acid:base). If the final \( [\ce{HZ}] = 0.06 \, \text{M} \), what is the pH?

Q7. For \( \ce{2A(g) + B(g) <=> 2C(g)} \), \( K_p = 16 \) at 400 K. If the total pressure at equilibrium is 5 atm and \( P_{\ce{A}} = 2 \, \text{atm} \), what is \( P_{\ce{C}} \)?

Q8. In \( \ce{A(g) + 2B(g) <=> C(g)} \), \( K_c = 8 \) and at equilibrium \( [\ce{A}] = 0.1 \, \text{M} \), \( [\ce{B}] = 0.2 \, \text{M} \), \( [\ce{C}] = 0.16 \, \text{M} \). What happens if the volume is doubled?

Q9. For \( \ce{A(g) + 3B(g) <=> 2C(g)} \), \( K_p = 0.125 \) at 600 K. If \( P_{\ce{A}} = 1 \, \text{atm} \), \( P_{\ce{B}} = 2 \, \text{atm} \) initially, what is \( P_{\ce{C}} \) at equilibrium?

Q10. For \( \ce{2NO2(g) <=> N2O4(g)} \), \( K_c = 200 \) at 298 K. If 0.1 mol \( \ce{NO2} \) is placed in a 1 L vessel, what is \( [\ce{N2O4}] \) at equilibrium?