Q45 of 55 Page 61

In the following questions a statement of Assertion (A) followed by a statement of Reason (R) is given. Choose the correct option out of the choices given below each question.

Assertion (A): At constant temperature, pVvs V plot for real gases is not a straight line.


Reason (R): At high pressure all gases have Z > 1 but at intermediate pressure most gases have Z < 1.


(i) Both A and R are true and R is the correct explanation of A.


(ii) Both A and R are true but R is not the correct explanation of A.


(iii) A is true but R is false.


(iv) A is false but R is true.


(ii)

We know that at constant temperature, pV vs V plot for real gases is not a straight line.


This is because, for pV vs V graph to be straight line, the volume of the gas should be negligible, but it is not possible for the real gases, because they have some volume and hence they show deviation from the straight line.


Now discussing reason,


At high pressure all gases have Z > 1 but at intermediate pressure most gases have Z < 1, this statement is true but it is not the correct explanation of Assertion.


Hence, (ii) is correct option.


More from this chapter

All 55 →
43

Match the following graphs of ideal gas with their co-ordinates:

 44

In the following questions a statement of Assertion (A) followed by a statement of Reason (R) is given. Choose the correct option out of the choices given below each question.

Assertion (A): Three states of matter are the result of balance between intermolecular forces and thermal energy of the molecules.


Reason (R): Intermolecular forces tend to keep the molecules together but thermal energy of molecules tends to keep them apart.


(i) Both A and R are true and R is the correct explanation of A.


(ii) Both A and R are true but R is not the correct explanation of A.


(iii) A is true but R is false.


(iv) A is false but R is true.


 46

In the following questions a statement of Assertion (A) followed by a statement of Reason (R) is given. Choose the correct option out of the choices given below each question.

Assertion (A): The temperature at which vapour pressure of a liquid is equal to the external pressure is called boiling temperature.


Reason (R): At high altitude atmospheric pressure is high.


(i) Both A and R are true and R is the correct explanation of A.


(ii) Both A and R are true but R is not the correct explanation of A.


(iii) A is true but R is false.


(iv)A is false but R is true.


 47

In the following questions a statement of Assertion (A) followed by a statement of Reason (R) is given. Choose the correct option out of the choices given below each question.

Assertion (A): Gases do not liquefy above their critical temperature, even on applying high pressure.


Reason (R): Above critical temperature, the molecular speed is high and intermolecular attractions cannot hold the molecules together because they escape because of high speed.


(i) Both A and R are true and R is the correct explanation of A.


(ii) Both A and R are true but R is not the correct explanation of A.


(iii) A is true but R is false.


(iv)A is false but R is true.