Skip to content
p.paperbanao.
Continue

Punjab (PTB) · Chapter test · Free

1st Year Chemistry Chapter 8 TestChemical Equilibrium

30 marks · 40 minutes · 21 questions. Covers: CHAP 8: Chemical Equilibrium.

Your school name

1st Year Chemistry Chapter 8 Test

1st Year · Chemistry · Punjab (PTB)

Name: ____________Roll No: ________Class/Section: ________Date: ________Total marks: 30Time: 40 minutes

Q1. Multiple choice questions (Attempt all · 10 × 1 = 10)

  1. Which type of equilibrium involves a change of state?

    1. Chemical

    2. Physical

    3. Ionic

    4. Molecular

  2. Which statement is true about a reversible reaction at equilibrium?

    1. All reactants are converted into products

    2. Microscopic changes stop

    3. The concentrations of products and reactants remain constant

    4. The reaction becomes irreversible

  3. Kc = 0.040 at 450oC for the given reaction, evaluate Kp for the reaction.

    1. 0.40

    2. 0.64

    3. 2.4

    4. 0.052

  4. What causes equilibrium concentrations to remain constant macroscopically?

    1. Reactions stop occurring

    2. No molecules move

    3. Equal rates of forward and reverse microscopic reactions

    4. Reactants are used up

  5. When BiC/3 reacts with H2O white ppt of BiOC/ is formed . The white ppt disappears when

    1. More BiCl3 is added

    2. BiCl3 is removed

    3. More H2O is added

    4. HC/ is removed

  6. Which of the following reactions will be favoured to the forward direction at low pressure:

  7. In a closed system at equilibrium, which event continues to occur at the particle level?

    1. Only product formation

    2. Forward and reverse reactions stop

    3. No further reaction occurs

    4. Reactants are converting to products and vice versa

  8. The value of equilibrium constant can predict:

    1. The direction of reaction

    2. The extent of reaction

    3. The effect of catalyst used

    4. Both the direction and extent of reaction

  9. At equilibrium, which of the following changes occur in concentration?

    1. Concentration of products keeps increasing

    2. No change in concentration of reactants or products

    3. Reactants suddenly disappear

    4. Only product concentration remains constant

  10. Which statement best describes chemical equilibrium?

    1. All reactions stop completely

    2. Product formation is complete

    3. Forward and reverse reactions occur at the same rate

    4. Only reactants remain

Q2. Short questions (Attempt any 6 of 8 · 6 × 2 = 12)

  1. Why does changing the concentration of a substance not alter the value of the equilibrium constant?

  2. The change of volume disturbs the equilibrium position for some of the gas phase reactions but not the equilibrium constant.

  3. How can you experimentally determine if a system is at equilibrium?

  4. Why are microscopic events considered continuous even when a reaction appears complete?

  5. State law of mass action.

  6. Why ice at 0 oC can be melted by applying pressure without supply of heat from outside?

  7. Reversible reaction attains the position of equilibrium which dynamic in nature and not static.Explain it.

  8. In an exothermic reversible reaction, what will be the effect of increasing tempera the position of equilibrium and why?

Q3. Long questions (Attempt any 2 of 3 · 2 × 4 = 8)

  1. Write down the Kc for the following reactions. Suppose that the reaction mixture in all the case is ‘V’ dm-3 (i) CH3COOH + CH3CH2OH (eq) CH3COOC2H5 + H2O (ii) 2HI (eq) H2 + I2 (iii) N2 + 3H2 2NH3

  2. Write the expressions for Kc for the following reactions: (i) Sn2+(aq)+2Fe3(aq) (eq) Sn4+(aq) + 2Fe2+(aq) (ii) Ag1+(aq) + Fe2+(aq) (eq) Fe3+(aq) + Ag(s) (iii) N2(g) + O2(g) (eq) 2NO(g) (iv) 4NH3(g) + 5O2(g) (eq) 4NO(g) + 6H2O(g) (v) PCl5(g) (eq) PCl3(g) + Cl2(g)

  3. The equilibrium constant for the reaction between acetic acid and ethyl alcohol is 4. A mixture of 3 moles of acetic acid and 1 mole of hole of ethyl alcohol is allowed to come to equilibrium. Calculate the amount of ethyl acetate present at equilibrium.