NEET Equilibrium — Set 4

Question 1

For $ \ce{N2O4(g) <=> 2NO2(g)} $, $ K_p = 0.16 $ at 400 K. If 0.5 moles of $ \ce{N2O4} $ are placed in a 1 L vessel, what is $ P_{\ce{NO2}} $ at equilibrium ($ R = 0.0831 \, \text{bar L/mol K} $)?

Accepted Answer

Initial: $ P_{\ce{N2O4}} = \frac{0.5 \times 0.0831 \times 400}{1} = 16.62 \, \text{bar} $. Let $ 2x = P_{\ce{NO2}} $, $ P_{\ce{N2O4}} = 16.62 - x $, total pressure = $ 16.62 + x $. $ K_p = \frac{(P_{\ce{NO2}})^2}{P_{\ce{N2O4}}} = \frac{(2x)^2}{16.62 - x} = 0.16 $, $ 4x^2 = 0.16 (16.62 - x) $, $ x \approx 0.8 $, $ P_{\ce{NO2}} = 1.6 \, \text{bar} $.

Question 2

Which species acts as a Bronsted-Lowry base?

Accepted Answer

$ \ce{HCO3-} $ can accept $ \ce{H+} $ to form $ \ce{H2CO3} $, making it a base.

Question 3

Which species can act as both a Bronsted-Lowry acid and base?

Accepted Answer

$ \ce{HS-} $ can donate $ \ce{H+} $ (acid) to form $ \ce{S^{2-}} $ or accept $ \ce{H+} $ (base) to form $ \ce{H2S} $, making it amphoteric.

NEET Chemistry: Equilibrium — Practice Set 4

Q1. For \( \ce{N2O4(g) <=> 2NO2(g)} \), \( K_p = 0.16 \) at 400 K. If 0.5 moles of \( \ce{N2O4} \) are placed in a 1 L vessel, what is \( P_{\ce{NO2}} \) at equilibrium (\( R = 0.0831 \, \text{bar L/mol K} \))?

Q2. Which species acts as a Bronsted-Lowry base?

Q3. Which species can act as both a Bronsted-Lowry acid and base?

Q4. For \( \ce{XY2(s) <=> X^{2+}(aq) + 2Y-(aq)} \), if \( K_{sp} = 2.7 \times 10^{-7} \), what is the solubility of \( \ce{XY2} \) in mol/L?

Q5. A weak acid \( \ce{HA} \) (\( K_a = 5.0 \times 10^{-6} \)) is mixed with 0.04 M \( \ce{NaOH} \) in a 2:1 volume ratio (acid:base). If the final \( [\ce{HA}] = 0.06 \, \text{M} \), what is the pH?

Q6. The solubility of \( \ce{Ag2CrO4} \) in 0.02 M \( \ce{K2CrO4} \) is \( 1.0 \times 10^{-5} \, \text{M} \). What is its \( K_{sp} \)?

Q7. What is the \( \text{pOH} \) of a 0.001 M solution of \( \ce{NaOH} \) assuming complete dissociation?

Q8. Which species can act as both a Lewis acid and base?

Q9. The \( K_a \) of \( \ce{HCN} \) is \( 4.9 \times 10^{-10} \). What is \( K_b \) of \( \ce{CN-} \) at 298 K?

Q10. For \( \ce{2A(g) + B(g) <=> 2C(g)} \), \( K_p = 4 \) 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?