Chemistry Class-11: Chapter –7. Equilibrium Part – 4

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II. Multiple Choice Questions (Type-II)

In the following questions two or more options may be correct.

Question: 20

For the reaction the value of is at and . Which of the following options is correct?

(i) The reaction is endothermic

(ii) The reaction is exothermic

(iii) If are mixed at at partial pressures bar and bar respectively, more will be formed.

(iv) The entropy of the system increases.

Answer:

(i), (iii) and (iv)

Justification:

(i) K increases with increase in temperature.

(iii) , Therefore, reaction proceeds in the backward direction.

(iv) , Therefore, .

Question: 21

At a particular temperature and atmospheric pressure, the solid and liquid phases of a pure substance can exist in equilibrium. Which of the following term defines this temperature?

(i) Normal melting point

(ii) Equilibrium temperature

(iii) Boiling point

(iv) Freezing point

Answer: (i) and (iv)

III. Short Answer Type

Question: 22

The ionisation of hydrochloric in water is given below:

Label two conjugate acid-base pairs in this ionisation.

Answer:

Question: 23

The aqueous solution of sugar does not conduct electricity. However, when sodium chloride is added to water, it conducts electricity. How will you explain this statement on the basis of ionisation and how is it affected by concentration of sodium chloride?

Answer:

Sugar does not ionise in water but ionises completely in water and produces and .

Conductance increases with increase in concentration of salt due to release of more ions.

Question: 24

does not have proton but still acts as an acid and reacts with . Why is it so? What type of bond is formed between the two?

Answer:

acts as a Lewis acid as it is electron deficient compound and coordinate bond is formed as given below:

Question: 25

Ionisation constant of a weak base , is given by the expression

Values of ionisation constant of some weak bases at a particular temperature are given below:

Arrange the bases in decreasing order of the extent of their ionisation at equilibrium. Which of the above base is the strongest?

Answer:

Order of extent of ionisation at equilibrium is as follows:

Since dimethylamine will ionise to the maximum extent it is the strongest base out of the four given bases.

Question: 26

Conjugate acid of a weak base is always stronger. What will be the decreasing order of basic strength of the following conjugate bases?

Answer:

Question: 27

Arrange the following in increasing order of .

Answer:

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