NCERT Solutions and CBSE MCQs will provide you an in-depth understanding of all the questions and concepts in NCERT Textbooks. Relationships between chemical equations and the expressions of equilibrium constants The expression of equilibrium constant depends on how the equilibrium equation is written. A. NH4+/NH3 E) in the presence of solid carbon, 35) The effect of a catalyst on an equilibrium is to ________. The heat of vaporization of the alcohol at 25 C is 45.4 kJ/mol, the specific heat of aluminum is 0.903 J/gC. . \mathrm{Co}^{2+}(\mathrm{aq})+2 \mathrm{e}^{-} \rightleftharpoons \mathrm{Co}(\mathrm{s}) & \text { voltage }=-0.28 \mathrm{~V} \\ E) an increase in total pressure by the addition of helium gas (V and T constant), B) a decrease in the total pressure (T constant), 33) Consider the following reaction at equilibrium: B) increase the partial pressure of CO2 (g) Nigeria, (+ What happens to the vapor pressure of a substance when the temperature is increased? The P-M AS-NM R chemical shift changes from -15.6 ppm ( 6 -hydrate) to - 1 1.0 ppm (anhydrous). for the following reaction at 25C: HI(g)12H2(g)+12I2(g), The given reaction is D. TP and CP are always at the same pressure. C. N(g) D -511. The equilibrium mixture contained 1.37 10 2 M HI, 6.47 10 3 M H2, and 5.94 10 4 M I2. E. 0.371, From Midterm Exam 2: \mathrm{Ag}^{+}(\mathrm{aq})+\mathrm{e}^{-} \rightleftharpoons \mathrm{Ag}(\mathrm{s}) & \text { voltage }=+0.80 \mathrm{~V} \\ C. 50.0 g Al, CAl = 0.903 J/gC 100.0C At 100 C and 1 atm, water is in which phase? All reactant and product concentrations are constant at equilibrium. 52) B. Xn2+ + 2 e- Xn(s) : E = 1.33 V C) roughly equal amounts of products and reactants are present 41) The osmotic pressures required for this process can be as high as 18.6 atm . 49) C. N2 C. -486 kJ At the same temperature, pure liquid A has a vapor pressure of 220 torr, while pure liquid B has a vapor pressure of 400 torr. 2HI (g) H2 (g) + I2 (g) A) 100 B) 0.50 C) 0.020 D) 2500 E) -50 C) 0.020 13) The Keq for the equilibrium below is 50. Guinea, (+ United Kingdom, (+ E) 2 Fe2O3 (s) 4 Fe (s) + 3O2 (g), 30) Based on Le Chtelier's principle, increasing pressure at constant temperature in the following reaction will not change the concentrations of reactants and products. 2 HD(g) H2(g) + D2(g) Kc = 0.28 A) the quantities of reactants and . Russia, (+ Part A: What is the value of E for the combustion of the fuel? D. 1, The equilibrium constant is given for two of the reactions below. Netherlands, (+ C) [H+][HCO3-] / [CO2][H2O] - A gas can be converted into a liquid by cooling. C. remove reactant Q: What is the [H3O+] in pure water at body temperature? D) 2500 A. 968) D) increase the value of the equilibrium constant From Midterm 3: (ii) The value of K decreases as the system approaches equilibrium. This reaction has been started at time t = 0 with an initial concentration of [A]0 = 0.3 M, with a half-life t1/2 = 131 s. What concentration of A is present at time t = 258 s ? C. State functions do not depend on the path taken to arrive at a particular state. 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For benzoic acid, Ka=6.5105. Initially, the vessel contains only X2 at a pressure of 1.75 atm. It permits everybody to download CBSE Class 12 Chemistry Chapter-wise MCQs question keep money with addresses in free pdf organization and practice them for additional investigations. 100 27.3 kJ mol-1 The system is losing 115 J, while the surroundings are gaining 115 J, A. energy associated with the temperature of an object, D. energy associated with the motion of an object, D. energy associated with the position or composition of an object. B. From Midterm 3: Ti (s) + 2Cl2 (g) TiCl4 (l) The enthalpy of a reaction can be calculated from the heats of formation of the substances involved in the reaction: A) The reaction quotient must be satisfied for equilibrium to be achieved. C) 0.020 B. Xd + 2 H+ 2 Xd+ + H2 Q: What is the percent ionization of ammonia at this concentration? H2 (g) + I2 (g) HI (g) Coming up next are not many significant advantages of CBSE MCQs with Answers for Class 12 Chemistry distributed by cbseMCQ.com: Q1. 2SO2 (g) + O2 (g) 2SO3 (g) A. Erxn can be determined using constant volume calorimetry. What is the boiling point of water at an elevation of 1.00104 ft ? 26) Which of the following statements is true? E) decrease the partial pressure of CO, D) increase the value of the equilibrium constant, 34) Consider the following reaction at equilibrium. The reaction mixture will contain [A]=0.1M and [B]=1.0M. C. 22.1 kJ mol-1 After a sufficiently long time, [A] will approach zero, regardless of the values of k and k'. D) [SO3]2 / [SO2]2[O2]2 Propane has a normal boiling point of 42.0C and a heat of vaporization (Hvap) of 19.04 kJ/mol. [A solution contains a mixture of pentane and hexane at room temperature. [The decomposition of SO2Cl2 is first order in SO2Cl2 and has a rate constant of 1.46104 s1 at a certain temperature] . A) 100 B. 48) D) [H3O+][F-] / [HF] 995) 355) A.1.89 103 J 973) Poland, (+ [Acid rain over the Great Lakes has a pH of about 4.6.] New Zealand, (+ User Agreement,Privacy Policy 380) VITEEE 2007: For the reaction H 2( g )+ I 2( g ) longrightarrow 2 HI ( g ), the equilibrium constant Kp changes with (A) total pressure (B) catalyst (VITEEE 2007: For the reaction H 2( g )+ I 2( g ) longrightarrow 2 HI ( g ), the equilibrium constant Kp changes with (A) total pressure (B) catalyst (Tardigrade - CET NEET JEE Exam App. . 10 D) Q does not depend on the concentrations or partial pressures of reaction components. Q: If the initial concentration of SO2Cl2 is 1.00 M, how long will it take for the concentration to decrease to 0.72 M ? is Keq = 3.6 10-3 at 999 K. At equilibrium, ________. 1) H2 (g) + I2 (g) <------------------> 2 HI (g) Given: 28) Which reaction will shift to the left in response to a decrease in volume? For a process at constant pressure, 49,600 calories of heat are released. B. E. -91 kJ, Identify an element that is NOT in its standard state. B. Detailed description of the questions is given by subject experts and you can use them as a reference during your preparation. 0.093 M [The half-life for the radioactive decay of U238 is 4.5 billion years and is independent of initial concentration] D. 0.117 M A2B(g) + B(g) A2B2(g) Kc = 16.4 Note: Names of real elements have been changed to 'Xd'. Part B: Calculate the work done, w. [A 100-W lightbulb is placed in a cylinder equipped with a moveable piston. 2SO2 (g) + O2 (g) 2SO3 (g) B) N2 (g) + O2 (g) 2NO (g) D) at low temperature and high pressure but the same value of Kc will be obtained at a given temperature. The lightbulb is turned on for 0.015 h, and the assembly expands from an initial volume of 0.90 L to a final volume of 5.89 L against an external pressure of 1.0 atm] E) Q is the same as Keq when a reaction is at equilibrium. and 1.72 What would the molar concentration of the tree sap have to be to achieve this pressure on a day when the temperature is 31 C ? Arsenic acid (H3AsO4) is a polyprotic acid with Ka1 = 5.510-3, Ka2 = 1.710-7, and Ka3 = 5.110-12. 7) Bangladesh, (+ E) The reaction is at equilibrium when Q = Keq. 973) 45) ..Keq = 6.2 x 10^2 Business, Finance, Economics, Accounting, Operations Management, Computer Science, Electrical Engineering, Mechanical Engineering, Civil Engineering, Chemical . Solution Verified by Toppr Correct option is D) For the reaction, H 2(g)+I 2(g)2HI(g), the number of moles of gaseous reactants is equal to the number of moles of gaseous products. Equilibrium constant Kp is equal to the partial pressure of products divided by partial pressure of reactants and the partial pressure are raised with some power which is equal to the coefficient of the substance in balanced equation. The concentration [A] was measured at two different times: at t1 = 19.4 s the concentration of A was [A]1 = 0.62 M and at time t2 = 60.8 s the result was [A]2 = 0.31 Q: How long will it take for 15% of the U238 atoms in a sample of U238 to decay? C. 5.25 J/(g C) H2 (g) + I2 (g) HI (g) A) 25 B) 2500 C) 7.07 D) 100 E) -50 C) 7.07 45) C. Xd2+ + 2 H+ Xd + H2 Mauritius, (+ at a certain temperature. 2 CH3OH(l) + 3 O2(g) 2 CO2(g) + 4 H2O(g) (a) total pressure(b) catalyst used(c) amount of H2 and I2(d) temperature, (a) 2 10-4(b) 4 10-2(c) 2 10-2(d) 1 10-2, (a) bar min-1, bar2 min-1(b) bar min-1, bar1/2 min-1(c) bar1/2 min-1, bar2 min-1(d) bar min-1, bar1/2 min-1, (a) 9 times(b) 4 times(c) 16 times(d) 8 times, (a) NH4NO2 N2 + 2H2O(b) NO + O3 NO2 + O2(c) 2NO + Br2 2NOBr(d) CH3CHO CH4 + CO, (a) mol L-1 s-1(b) s-1(c) mol-2 L s-1(d)mol L-1, (a) (i)2, (ii) 1(b) (i)2,(ii) 2(c) (i) 1, (ii) 1(d) (i) 1, (ii) 2, (a) temperature of the reaction(b) extent of the reaction(c) initial concentration of the reactants(d) the time of completion of reaction, (a) Rate = k [O] [O3](b) Rate = k [O3] [O2]-1(c) Rate = k [O3](d) Rate = k [O2] [O], (a) zero order reaction(b) first order reaction(c) second order reaction(d) third order reaction, (a) order of a reaction(b) molecuiarity of a reaction(c) fast step of the mechanism of a reaction(d) half-life of the reaction, (a) the order and molecuiarity of the slowest step are equal to one(b) molecuiarity of the reaction can be zero, one or two(c) molecuiarity of the reaction can be determined only experimentally(d) more than one reacting species are involved in one step, (a) the order and molecuiarity of the slowest step are equal to one, (a) the rate of fastest intermediatestep(b) the sum total of the rates of all intermediate steps(c) the average of the rates of all the intermediate steps(d) the rate of slowest intermediate step, (d) the rate of slowest intermediate step, (a) temperature(b) mechanism of reaction as well as relative concentration of reactants(c) molecularity(d) pressure, (b) mechanism of reaction as well as relative concentration of reactants, (a) inversely proportional to the concentration units(b) independent of concentration units(c) directly proportional to concentration units(d) inversely proportional to the square of concentration units, (a) 2 10-2 s-1(b) 4 10-4 s-1(c) 20 s-1(d) 2 10-4 s-1, (a) EaR(b) Ea2.303R(c) 2.303Ea.R(d) Ea2.303, (a) mol L-1s-1(b) s-1(c) L mol-1s-1(d) L2mol-2s-1, (a) triple(b) increase by a factor of 4(c) double(d) remain unchanged. E. -24.5 kJ, Calculate the amount of heat (in kJ) required to raise the temperature of a 79.0 g sample of ethanol from 298.0 K to 385.0 K. The specific heat capacity of ethanol is 2.42 J/gC. Consider the chemical equation and equilibrium constant at 25C: B) 0.50 Q: How long will it take for the concentration of SO2Cl2 to decrease to 25% of its initial concentration? You can utilize the quick links on our page to view or download the CBSE MCQs of all classes in an easy way. 966) Decreased? Qc = 0.120 < Kc reaction proceeds to products. Portugal, (+ 2.34 10-7 C) 7.07 From Midterm 3: E) The reaction will go to completion since there are equal amounts of Br2 and Cl2. 28.4 kJ 1) A. A. What is the primary source of water stored in an aquifer? C. surface tension Understudies can get to the CBSE NCERT MCQ Questions of Class 12 Chemistry with Answers Pdf of all Chapters liberated from cost from here. A) The equilibrium partial pressures of Br2, Cl2, and BrCl will be the same as the initial values. 358) From Midterm Exam 2: +238 kJ Check all that apply. Turkey, (+ Q6. United States, (+ CH3NC(g) CH3CN(g) In each table, there may be one statement that is false because it contradicts the other three statements. C. 3.42 torr E. All of the above are true. B. H2SO3/HSO3- D. CH3OH, D. CH3OH A P 355) A B + C 960) 48) E. methanol, Give the major force between ethanol and water. E. 0.169 M, From Midterm Exam 2: What is the stoichiometric coefficient of Xx(s) in the balanced reaction equation for that cell ? 30.5 C [An object can possess kinetic energy, the energy of motion, and/or potential energy, the energy of position. D. 1-butanol C) 2 SO3 (g) 2 SO2 (g) + O2 (g) C) N2 (g) + 2O2 (g) 2NO2 (g) (iii) The total pressure increases as the system approaches equilibrium. Comprehend the ideas and practice Objective Type Questions for twelfth Class Chemistry however much you can to score well. You will track down a rundown of Chapter wise MCQ Questions with Answers for CBSE Class 12 Chemistry here to start your planning. Bangladesh, (+ A. C) N2 (g) + 3H2 (g) 2 NH3 (g) 31) The molar mass of sugar is 342.3 g/mol. 2.35 x 104 kJ/mole D. At any time, the ratio [P] / [A] is equal to k' / k. 855) A. PO43- Find the equilibrium amounts of these compounds if they all start out at 0.120 M. Solution: Determine Qc so that you know which direction the reaction will proceed. 971) A reaction of the type 2A P has the following rate law: rate = k[A]2. B. The isomerization of methylisonitrile to acetonitrile D. - 1.23 x 103 kJ/mole. (Methanol ( CH3OH ) contains hydrogen directly bonded to oxygen, so it has hydrogen bonding. 2003-2023 Chegg Inc. All rights reserved. H2 (g) + I2 (g)-- > < -- 2HI(g) H=-10.4 kJ. 2SO3 (g) 2SO2 (g) + O2 (g) The symbols have their usual meaning, for example AG stands for the standard Gibbs free energy of reaction and K stands for the equilibrium constant. A sample of NO gas was introduced into a container such that the initial partial pressure of NO was 560 torr. What is the hydronium ion concentration of a 0.150 M hypochlorous acid solution with K a = 3.5 10-8? Denmark, (+ H2(g) +I2(g) 2HI(g) Using the Equilibrium Constant (cont) E.g.2 For the reaction: PCl5(g) PCl3(g) + Cl2(g), Kc = 0.800 M at 340oC. C) N2 (g) + 2O2 (g) 2NO2 (g) A. F2 Consider the equilibrium of two (ideal) gases according to 2A A2 with equilibrium constant K = 2.010-3 at a pressure of 1 bar and 30C. A 250 mL sealed flask contains 0.65 g of butane at 22C.] Additionally, you can reconsider all Chemistry sections appropriately whenever and save significant season of yours during class tests and yearly tests readiness. Another example of a chemical equation that can be used to explain is given below: Equation: 2 S O 2 ( g) + O 2 ( g) 2 S O 3 ( g) Equilibrium Constant: K C = [ S O 3] 2 [ S O 2] 2 [ O 2] Moreover, in terms of finding equilibrium constant for gases, partial pressure is taken into account. Part A: Use the wattage of the lightbulb and the time it is on to calculate the heat transferred, q, in joules. Which statement describes best the pH of a 0.010 M solution of this acid. Egypt, (+ The statements in the tables below are about two different chemical equilibria. B. HPO42- D. The value of pH is somewhat lower than 2.13. An analyte containing 0.12 L of a 0.025 M solution of a strong acid is titrated with a 0.220 M solution of a strong base. A) Q does not change with temperature. Provide your answer in units of mol L-1. subject to the given initial conditions. 07 H2(g) Nonmetal Gas 2 00 L container and goes to equilibrium at 200 oC 00 L container and goes to equilibrium at 200 oC.