Law of mass action, Kc and Kp

28 questions on Law of mass action, Kc and Kp from the Chemical Equilibrium chapter: 6 NEET level, 11 JEE Main, 11 JEE Advanced. Each one opens with its answer and solution.

• What is the expression for K_c for the reaction N2(g) + 3H2(g) <=> 2NH3(g)? NEET level
• For the equilibrium CaCO3(s) <=> CaO(s) + CO2(g), the correct expression for K_c is NEET level
• For which of the following reactions is K_p = K_c (at any temperature)? NEET level
• At a certain temperature, K_c = 5.0 for X(g) <=> Y(g). What is K_c for the reaction 2Y(g) <=> 2X(g) at the same temperature? NEET level
• For a reaction at a given temperature, K_c = 50 and the reaction quotient is Q_c = 20. Which statement is correct? NEET level
• What are the units of K_c for N2(g) + 3H2(g) <=> 2NH3(g) if concentrations are in mol/L? NEET level
• In a 1 L vessel at equilibrium, [SO2] = 0.20 M, [O2] = 0.10 M and [SO3] = 0.40 M for 2SO2(g) + O2(g) <=> 2SO3(g). The value of K_c (in L mol^-1) is JEE Main level
• For CaCO3(s) <=> CaO(s) + CO2(g), K_p = 0.80 atm at 1000 K. Taking R = 0.0821 L atm mol^-1 K^-1, K_c (in mol L^-1) at this temperature is JEE Main level
• At a given temperature, K_c = 2.0 for X <=> Y and K_c = 3.0 for Y <=> Z (all species gaseous). What is K_c for 2X <=> 2Z at this temperature? JEE Main level
• For H2(g) + I2(g) <=> 2HI(g), K_c = 50 at a certain temperature. A 5.0 L flask contains 0.50 mol H2, 0.50 mol I2 and 3.00 mol HI. Which statement is correct? JEE Main level
• PCl5(g) is 40% dissociated at a total pressure of 2.0 atm at equilibrium: PCl5(g) <=> PCl3(g) + Cl2(g). The value of K_p (in atm) is JEE Main level
• 1.0 mol of H2 and 1.0 mol of I2 are heated in a 2.0 L vessel. At equilibrium, 1.3 mol of HI is present: H2(g) + I2(g) <=> 2HI(g). Calculate K_c and give the ans... JEE Main level
• For N2O4(g) <=> 2NO2(g), K_c = 0.50 mol L^-1 at 400 K. Use R = 0.0821 L atm mol^-1 K^-1 and calculate K_p in atm, to two decimal places. JEE Main level
• 0.50 mol of PCl5 is placed in a 5.0 L closed vessel and it dissociates 40% at equilibrium, PCl5(g) <=> PCl3(g) + Cl2(g). Calculate K_c in mol L^-1 and report K_... JEE Main level
• PCl5 dissociates to the extent of 30% at a total equilibrium pressure of 1.5 atm, PCl5(g) <=> PCl3(g) + Cl2(g). Calculate K_p in atm, to two decimal places. JEE Main level
• Which of the following statements about equilibrium constants are correct? JEE Main level
• For which of the following reactions is K_p = K_c at all temperatures? JEE Main level
• Pure A(g) at 2.0 atm is introduced into a rigid vessel at constant temperature, where A(g) <=> 2B(g) is established. The total pressure at equilibrium is 3.0 at... JEE Advanced level
• N2O4(g) (molar mass 92 g/mol) partly dissociates as N2O4(g) <=> 2NO2(g). At a total pressure of 1.0 atm, the equilibrium mixture has a vapour density (relative ... JEE Advanced level
• At a certain temperature, K_c = 1.6 x 10^-3 for N2(g) + O2(g) <=> 2NO(g) and K_c = 2.5 x 10^2 for 2NO(g) + O2(g) <=> 2NO2(g). What is K_c at this temperature fo... JEE Advanced level
• Solid NH4HS decomposes in an evacuated rigid vessel: NH4HS(s) <=> NH3(g) + H2S(g). The total pressure at equilibrium is 0.60 atm. Extra NH3 is then injected at ... JEE Advanced level
• 1.0 mol of H2 and 2.0 mol of I2 are heated in a 1.0 L closed vessel where H2(g) + I2(g) <=> 2HI(g) has K_c = 54. Calculate the amount of HI at equilibrium, in m... JEE Advanced level
• 1.0 mol of NH3 decomposes in a closed vessel at constant total pressure of 5.0 atm: 2NH3(g) <=> N2(g) + 3H2(g). At equilibrium, 30% of the NH3 has decomposed. C... JEE Advanced level
• For 2SO2(g) + O2(g) <=> 2SO3(g), K_p = 0.40 atm^-1 at 800 K. Use R = 0.0821 L atm mol^-1 K^-1 and calculate K_c (in L mol^-1) to the nearest integer. JEE Advanced level
• Carbon and carbon dioxide react as C(s) + CO2(g) <=> 2CO(g) with K_p = 1.60 atm at a given temperature. The total pressure of the gas mixture at equilibrium is ... JEE Advanced level
• For 2SO2(g) + O2(g) <=> 2SO3(g), K_c = 200 L mol^-1 at 500 K (use R = 0.0821 L atm mol^-1 K^-1). Which statements are correct at this temperature? JEE Advanced level
• For H2(g) + I2(g) <=> 2HI(g), K_c = 50 at a given temperature. Four mixtures are prepared in vessels at this temperature. A mixture with Q_c = K_c is already at... JEE Advanced level
• 1.0 mol of PCl5(g) dissociates (PCl5(g) <=> PCl3(g) + Cl2(g)) to the extent of 50% at a total equilibrium pressure of 1.00 atm and temperature T. Which statemen... JEE Advanced level