Consider the following equilibrium, mathrmCO(mathrmg) + 2mathrmH_2(mathrmg) rightleftharpoons mathrmCH_3mathrmOH(mathrmg) 0.1 mol of CO along with a catalyst is present in a 2mathrmdm^3 flask maintained at 500mathrmK. Hydrogen is introduced into the flask until the pressure is 5 bar and 0.04 mol of mathrmCH_3mathrmOH is formed. The mathrmK_p^0 is times 10^-3 (nearest integer). Given: mathrmR = 0.08mathrmdm^3cdottextbarcdotmathrmK^-1cdottextmol^-1 Assume only methanol is formed as the product and the system follows ideal gas behaviour.

Numerical Answer Type:
Enter a numerical value Answer: 74 to 74 +4 marks

Solution & Explanation

### Related Formula Ideal Gas equation layout for aggregate systems: P_texttotal cdot V = n_texttotal cdot RT Partial Pressure expression using mole fractions: p_i = X_i cdot P_texttotal ### Core Logic Let's tabulate equilibrium progress row-by-row: * Reaction matrix: beginarraylcccc & mathrmCO(g) & + & mathrm2H_2(g) & rightleftharpoons & mathrmCH_3OH(g) \\ t=0 & 0.1 & & a & & 0 \\ t_texteq & 0.1 - x & & a - 2x & & x endarray * Given x = 0.04mathrm~mol at equilibrium: - n_mathrmCO = 0.1 - 0.04 = 0.06mathrm~mol - n_mathrmCH_3OH = 0.04mathrm~mol * Determine total moles via system pressure (P = 5mathrm~bar, V = 2mathrm~L, T = 500mathrmK): 5 times 2 = n_texttotal times 0.08 times 500 implies n_texttotal = frac1040 = 0.25mathrm~mol * Find remaining unknown hydrogen moles: n_texttotal = 0.06 + n_mathrmH_2 + 0.04 = 0.25 implies n_mathrmH_2 = 0.15mathrm~mol ### Step 1: Calculate Kp Compute partial pressures using fractional allocation fractions (n_texttotal = 0.25): * p_mathrmCH_3OH = frac0.040.25 times 5 = 0.8mathrm~bar * p_mathrmCO = frac0.060.25 times 5 = 1.2mathrm~bar * p_mathrmH_2 = frac0.150.25 times 5 = 3.0mathrm~bar Substitute these pressures into the equilibrium expression: K_p = fracp_mathrmCH_3OHp_mathrmCO cdot (p_mathrmH_2)^2 = frac0.81.2 times 3^2 = frac0.810.8 = 0.07407 = 74.07 times 10^-3 Rounding to the nearest integer yields 74. ### Pattern Recognition Finding the total moles using the Ideal Gas Law from the final equilibrium pressure and volume cuts down steps, as it avoids explicitly computing the initial hydrogen amount 'a' first. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Chemistry: Equilibrium

More Equilibrium Previous-Year Questions — Page 5

Q76 jee_main_2024_27_jan_morning Salt Hydrolysis
Given below are two statements: Statement (I): Aqueous solution of ammonium carbonate is basic. Statement (II): Acidic/basic nature of salt solution of a salt of weak acid and weak base depends on K_a and K_b value of acid and the base forming it. In the light of the above statements, choose the most appropriate answer from the options given below :
  • A. Both Statement I and Statement II are correct
  • B. Statement I is correct but Statement II is incorrect
  • C. Both Statement I and Statement II are incorrect
  • D. Statement I is incorrect but Statement II is correct

Solution

### Related Formula pH of a weak acid-weak base salt system: textpH = 7 + frac12(textpK_a - textpK_b) ### Core Logic Ammonium carbonate, (textNH_4)_2textCO_3, is formed from a weak acid (textH_2textCO_3, K_a approx 4.3 times 10^-7) and weak base (textNH_4textOH, K_b approx 1.8 times 10^-5). Since K_b > K_a, the aqueous medium accumulates an excess of hydroxyl particles over hydronium, forming a basic system (textpH > 7). Both statements are structurally accurate descriptions. ### Chapter Mix Class 11 Chemistry: Equilibrium
Q84 jee_main_2024_29_jan_morning Kp and Kc Relationship
For the reaction mathrmN_2mathrmO_4(mathrmg) rightleftharpoons 2mathrmNO_2(mathrmg) mathrmK_p = 0.492 atm at 300mathrmK . mathrmK_c for the reaction at same temperature is \_\_\_\_\_\_ times 10^-2 . (textGiven: R = 0.082 text L atm mathrmmol^-1 textK^-1)
Numerical Answer. Answer: 2 to 2

Solution

### Related Formula K_p = K_c cdot (RT)^Delta n_g ### Core Logic For the given gaseous equilibrium reaction: N_2O_4(g) rightleftharpoons 2NO_2(g) First, find the change in the number of moles of gas (Delta n_g): Delta n_g = n_p - n_r = 2 - 1 = 1 ### Step 1: Calculation Substitute the given values into the K_p - K_c relationship: K_p = 0.492 R = 0.082 T = 300text K 0.492 = K_c cdot (0.082 times 300)^1 K_c = frac0.4920.082 times 300 K_c = frac0.49224.6 K_c = 0.02 Converting to the requested format (x times 10^-2): K_c = 2 times 10^-2 So, the value is 2. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Chemistry: Equilibrium
Q85 jee_main_2024_30_january_evening Buffer Solutions
The pH of an aqueous solution containing 1M benzoic acid (pK_a = 4.20) and 1M sodium benzoate is 4.5. The volume of benzoic acid solution in 300 mL of this buffer solution is ______ mL.
Numerical Answer. Answer: 100 to 100

Solution

### Related Formula Henderson-Hasselbalch Equation for Acidic Buffers: mathrmpH = pK_a + log left( frac[textSalt][textAcid] right) ### Core Logic Let the volume of 1M Benzoic acid be V_a mL and the volume of 1M Sodium benzoate be V_s mL. Total volume = V_s + V_a = 300\,textmL. Millimoles of acid = 1 times V_a = V_a Millimoles of salt = 1 times V_s = V_s Applying Henderson's Equation: 4.5 = 4.2 + log left(fracV_sV_aright) ### Step 1: Calculate Volume Ratio log left(fracV_sV_aright) = 4.5 - 4.2 = 0.3 Since log 2 approx 0.3, we have: fracV_sV_a = 2 V_s = 2 V_a ### Step 2: Substitute and Solve We know V_s + V_a = 300 Substituting V_s = 2 V_a: 2 V_a + V_a = 300 3 V_a = 300 V_a = 100 \, textmL ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Chemistry: Equilibrium
Q82 jee_main_2024_30_jan_morning Solubility Product
The pH at which Mg(OH)_2 [K_sp=1times 10^-11] begins to precipitate from a solution containing 0.10text M Mg^2+ ions is
Numerical Answer. Answer: 9 to 9

Solution

### Related Formula K_sp = [Mg^2+][OH^-]^2 pOH = -log[OH^-] pH + pOH = 14 ### Core Logic Precipitation begins just when the ionic product equals the solubility product (Q_sp = K_sp). ### Step 1: Calculating required [OH-] [Mg^2+][OH^-]^2 = 10^-11 Given [Mg^2+] = 0.10 text M 0.10 times [OH^-]^2 = 10^-11 [OH^-]^2 = 10^-10 [OH^-] = 10^-5 text M ### Step 2: Finding pH pOH = -log(10^-5) = 5 pH = 14 - pOH pH = 14 - 5 = 9 ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Chemistry: Equilibrium
Q71 jee_main_2024_31_jan_evening Equilibrium Constants (Kp and Kc)
A_(g) rightleftharpoons B_(g) + fracC2_(g) The correct relationship between K_P, alpha and equilibrium pressure P is
  • A. K_P = fracalpha^frac12P^frac12(2 + alpha)^frac12
  • B. K_P = fracalpha^frac32P^frac12(2 + alpha)^frac12(1 - alpha)
  • C. K_P = fracalpha^frac12P^frac32(2 + alpha)^frac32
  • D. K_P = fracalpha^frac12P^frac12(2 + alpha)^frac32

Solution

### Related Formula K_P = fracP_B cdot (P_C)^frac12P_A where P_i is the partial pressure of component i. ### Step 1: Setting up the ICE Table For the reaction A_(g) rightleftharpoons B_(g) + frac12 C_(g) Let initial moles of A = 1. At equilibrium: Moles of A = 1 - alpha Moles of B = alpha Moles of C = fracalpha2 Total moles at equilibrium = (1 - alpha) + alpha + fracalpha2 = 1 + fracalpha2 = frac2 + alpha2 ### Step 2: Calculating Partial Pressures Using mole fraction times Total Pressure (P): P_A = frac1 - alpha1 + fracalpha2 cdot P P_B = fracalpha1 + fracalpha2 cdot P P_C = fracfracalpha21 + fracalpha2 cdot P ### Step 3: Calculating Kp K_P = fracP_B cdot (P_C)^frac12P_A K_P = fracleft( fracalpha1 + alpha/2 P right) cdot left( fracalpha/21 + alpha/2 P right)^1/2frac1 - alpha1 + alpha/2 P K_P = fracalpha cdot (alpha/2)^1/2 cdot P^3/2(1 + alpha/2)^3/2 cdot frac1 + alpha/2(1 - alpha) P K_P = fracalpha^3/2 cdot P^1/2sqrt2 cdot (1 + alpha/2)^1/2 cdot (1 - alpha) Since 1 + alpha/2 = frac2+alpha2, the sqrt2 in denominator cancels out perfectly leaving: K_P = fracalpha^frac32 P^frac12(2 + alpha)^frac12(1 - alpha) ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Chemistry: Equilibrium
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JEE Physics: Waves (+15.5%) | Electrostatics: Concentric Shells (-29.7%) | Modern Physics: Photoelectric Clones (+34.2%) | Mathematics: Definite Integrals (+18.1%) | Chemistry: Coordination Splitting (-11.4%) | JEE Physics: Waves (+15.5%) | Electrostatics: Concentric Shells (-29.7%) | Modern Physics: Photoelectric Clones (+34.2%) | Mathematics: Definite Integrals (+18.1%) | Chemistry: Coordination Splitting (-11.4%)