NEET Equilibrium — Set 16

Question 1

For $ \ce{2A(g) + B(g) <=> 2C(g)} $, $ K_p = 16 $ at 500 K. If initial pressures are $ P_{\ce{A}} = 2 \, \text{atm} $, $ P_{\ce{B}} = 1 \, \text{atm} $, what is $ P_{\ce{C}} $ at equilibrium?

Accepted Answer

Let $ P_{\ce{C}} = 2x $, $ P_{\ce{A}} = 2 - 2x $, $ P_{\ce{B}} = 1 - x $, total pressure = $ 3 - x $. $ K_p = \frac{(P_{\ce{C}})^2}{P_{\ce{A}}^2 P_{\ce{B}}} = \frac{(2x)^2}{(2 - 2x)^2 (1 - x)} = 16 $, $ \frac{4x^2}{4(1 - x)^2 (1 - x)} = 16 $, $ \frac{x^2}{(1 - x)^3} = 4 $, $ \frac{x}{1 - x} = 2 $, $ x = 2 - 2x $, $ 3x = 2 $, $ x = \frac{2}{3} $, $ P_{\ce{C}} = 2 \times \frac{2}{3} = 1.33 \, \text{atm} $.

Question 2

For the reaction $ \ce{CO(g) + Cl2(g) <=> COCl2(g)} $, if $ K_c = 9 $ and initial concentrations are $ [\ce{CO}] = 0.3 \, \text{M} $, $ [\ce{Cl2}] = 0.3 \, \text{M} $, what is $ [\ce{COCl2}] $ at equilibrium?

Accepted Answer

Let $ [\ce{COCl2}] = x $, $ [\ce{CO}] = 0.3 - x $, $ [\ce{Cl2}] = 0.3 - x $. $ K_c = \frac{[\ce{COCl2}]}{[\ce{CO}][\ce{Cl2}]} = \frac{x}{(0.3 - x)^2} = 9 $. Solving, $ \sqrt{\frac{x}{0.3 - x}} = 3 $, $ \frac{x}{0.3 - x} = 9 $, $ x = 2.7 - 9x $, $ 10x = 2.7 $, $ x = 0.27 \, \text{M} $.

Question 3

The $ K_w $ of water at 373 K is $ 1.0 \times 10^{-12} $. What is the pH of pure water at this temperature?

Accepted Answer

$ K_w = [\ce{H+}][\ce{OH-}] = 1.0 \times 10^{-12} $, $ [\ce{H+}] = \sqrt{1.0 \times 10^{-12}} = 1.0 \times 10^{-6} $, $ \text{pH} = -\log(1.0 \times 10^{-6}) = 6 $.

NEET Chemistry: Equilibrium — Practice Set 16

Q1. For \( \ce{2A(g) + B(g) <=> 2C(g)} \), \( K_p = 16 \) at 500 K. If initial pressures are \( P_{\ce{A}} = 2 \, \text{atm} \), \( P_{\ce{B}} = 1 \, \text{atm} \), what is \( P_{\ce{C}} \) at equilibrium?

Q2. For the reaction \( \ce{CO(g) + Cl2(g) <=> COCl2(g)} \), if \( K_c = 9 \) and initial concentrations are \( [\ce{CO}] = 0.3 \, \text{M} \), \( [\ce{Cl2}] = 0.3 \, \text{M} \), what is \( [\ce{COCl2}] \) at equilibrium?

Q3. The \( K_w \) of water at 373 K is \( 1.0 \times 10^{-12} \). What is the pH of pure water at this temperature?

Q4. For \( \ce{2NO(g) + Cl2(g) <=> 2NOCl(g)} \), \( K_p = 9 \) at 500 K. If initial pressures are \( P_{\ce{NO}} = 1 \, \text{atm} \), \( P_{\ce{Cl2}} = 0.5 \, \text{atm} \), what is \( P_{\ce{NOCl}} \) at equilibrium?

Q5. For \( \ce{2A(g) + B(g) <=> 3C(g)} \), \( K_p = 9 \) at 500 K. If \( P_{\ce{A}} = 0.5 \, \text{atm} \), \( P_{\ce{B}} = 0.5 \, \text{atm} \), and \( P_{\ce{C}} = 1.5 \, \text{atm} \) at equilibrium, what happens if pressure is doubled?

Q6. The \( K_{sp} \) of \( \ce{Mg(OH)2} \) is \( 1.8 \times 10^{-11} \). What is the solubility of \( \ce{Mg(OH)2} \) in pure water in mol/L?

Q7. In the equilibrium \( \ce{A(g) <=> 2B(g)} \), what happens if \( \ce{B} \) is removed at constant volume?

Q8. A weak base \( \ce{BOH} \) (\( K_b = 4.0 \times 10^{-5} \)) has a 0.05 M solution with 2% ionization. What is the pH?

Q9. For \( \ce{2NO2(g) <=> N2O4(g)} \), if \( K_p = 4.0 \) at 350 K (\( R = 0.0831 \, \text{bar L/mol K} \)), what is \( K_c \)?

Q10. The \( K_{sp} \) of \( \ce{Fe(OH)3} \) is \( 4.0 \times 10^{-38} \). What is the pH at which \( [\ce{Fe^{3+}}] = 1.0 \times 10^{-10} \, \text{M} \) in a saturated solution?