1 Increasing the concentration of a reactant in an equilibrium mixture will: A shift equilibrium to the right B shift equilibrium to the left C stop the forward reaction D have no effect on equilibrium
2 According to Le Chatelier's principle, if the concentration of a product is decreased, the equilibrium shifts: A To the left B To the right C No shift D Becomes unpredictable
3 The value of the equilibrium constant K depends on: A Initial concentrations B Temperature C Pressure D Volume
4 Increasing pressure on a gaseous equilibrium shifts it toward the side with: A fewer moles of gas B more moles of gas C equal moles of gas D no gas at all
5 In a reversible reaction at dynamic equilibrium, which statement is true? A Forward reaction stops completely B Backward reaction stops completely C Forward and backward reactions occur at equal rates D Concentrations of reactants and products become zero
6 For the equilibrium PCl5(g) ⇌ PCl3(g) + Cl2(g), increasing the volume of the container will: A shift equilibrium to the left B shift equilibrium to the right C increase the total pressure D have no effect on equilibrium
7 Which of the following is an example of physical equilibrium? A water ⇌ water vapour in a closed container B burning of paper C rusting of iron D reaction of sodium with water
8 What does a double arrow (⇌) in a chemical equation represent? A The reaction is irreversible B The reaction is reversible C The reaction is exothermic D The reaction is endothermic
9 The role of a catalyst in a reversible reaction at equilibrium is to: A increase the yield of products B shift equilibrium to the right C help reach equilibrium faster D change the equilibrium constant
10 For the equilibrium N2(g) + 3H2(g) ⇌ 2NH3(g), increasing the pressure will: A shift equilibrium to the left B shift equilibrium to the right C decrease the value of Kc D have no effect on equilibrium
11 بند نظام میں حرکی توازن کے دوران درج ذیل میں سے کیا مستقل رہتا ہے؟ A صرف آگے کی رفتار B صرف پیچھے کی رفتار C ری ایکٹنٹس اور مصنوعات کی مقدارِ ارتکاز D مخلوط کا رنگ ہمیشہ
12 In a closed system at equilibrium, if the concentration of a product is decreased, the reaction will: A move in the forward direction B move in the backward direction C stop at once D remain unchanged
13 At dynamic equilibrium, the rate of the forward reaction is: A Greater than the rate of the backward reaction B Less than the rate of the backward reaction C Equal to the rate of the backward reaction D Zero
14 For the reaction N2(g) + 3H2(g) ⇌ 2NH3(g), what is the effect of increasing pressure on the equilibrium? A It shifts to the left. B It shifts to the right. C It has no effect. D It changes the equilibrium constant.
15 For an endothermic reaction at equilibrium, increasing the temperature will: A Shift equilibrium to the right B Shift equilibrium to the left C Decrease the equilibrium constant D Have no effect
16 Which of the following is a physical equilibrium? A H2(g) + I2(g) ⇌ 2HI(g) B Water ⇌ Ice C N2(g) + 3H2(g) ⇌ 2NH3(g) D 2SO2(g) + O2(g) ⇌ 2SO3(g)
17 For an endothermic reaction at equilibrium, increasing temperature will: A shift equilibrium in the forward direction B shift equilibrium in the backward direction C decrease the value of Kc D not affect the equilibrium
18 A reversible reaction can reach equilibrium only if it takes place in a: A Open system B Closed system C Vacuum D Catalyst
19 Which of the following is an irreversible reaction? A N2 + 3H2 ⇌ 2NH3 B H2 + I2 ⇌ 2HI C 2H2 + O2 → 2H2O D CaCO3 ⇌ CaO + CO2
20 In a closed system, when does a reversible reaction reach dynamic equilibrium? A When the forward reaction stops B When the backward reaction stops C When both reactions proceed at equal rates D When all reactants are consumed
21 What is the role of a catalyst in a reversible reaction at equilibrium? A It increases the rate of both forward and backward reactions equally. B It shifts the equilibrium to the forward direction. C It shifts the equilibrium to the backward direction. D It changes the value of the equilibrium constant.
22 Which change will increase the yield of ammonia in the Haber process? N2(g) + 3H2(g) ⇌ 2NH3(g) + heat A Increase in temperature B Decrease in pressure C Increase in pressure D Adding a catalyst
23 What is the effect of adding more reactant to a system at equilibrium? A Equilibrium shifts to the left B Equilibrium shifts to the right C Equilibrium does not change D The reaction stops
25 A closed system is necessary for dynamic equilibrium because: A reactants cannot be added B products cannot be removed C matter cannot enter or leave D temperature remains constant