Problem 79
Under what conditions gases generally deviate from ideal behaviour? (a) At high temperature and low pressure (b) At low temperature and high pressure (c) At high temperature and high pressure (d) At low temperature and low pressure
Problem 80
Compressibility factor of a gas is given by the equation \(Z=\frac{P V}{n R T} .\) On this basis, mark the correct statement. (a) When \(Z>1\), real gases get compressed easily. (b) When \(Z=1\) real gases get compressed easily. (c) When \(Z>1\), real gases are difficult to compress. (d) When \(Z=1\), real gases are difficult to compress
Problem 81
At Boyle's temperature, compressibility factor \(Z\) for a real gas is (a) 1 (b) 0 (c) \(>1\) (d) \(<1\)
Problem 82
It is observed that \(\mathrm{H}_{2}\) and He gases always show positive deviation from ideal behaviour i.e., \(Z>1\). This is because (a) the value of \(a\) is very large due to high attractive forces (b) the weak intermolecular forces of attraction due to which \(a\) is very small and \(a / V^{2}\) is negligible (c) the value of \(b\) is very large due to large size of the molecules (d) both \(a\) and \(b\) are very small and negligible.
Problem 84
What are the most favourable conditions to liquefy a gas? (a) High temperature and high pressure (b) Low temperature and high pressure (c) Low temperature and low pressure (d) High temperature and low pressure
Problem 85
It is easier to liquefy ammonia than oxygen because (a) it is easier to compress oxygen than \(\mathrm{NH}_{3}\) (b) \(\mathrm{NH}_{3}\) has a very low critical temperature as compared to \(\mathrm{O}_{2}\) (c) \(\mathrm{O}_{2}\) has a higher value of van der Waals constant \(a\) and higher critical temperature than \(\mathrm{NH}_{3}\) (d) \(\mathrm{NH}_{3}\) has a higher value of van der Waals constant \(a\) and higher critical temperature than oxygen.
Problem 86
Read the following statements and identify the incorrect statement. (a) Volume of one mole of a gas at critical temperature is called molar volume. (b) Pressure of a gas at critical temperature is called critical pressure. (c) The critical temperature, pressure and volume are called critical constants. (d) Critical temperature is the highest temperature at which a gas can exist as liquid, above this temperature it is a gas.
Problem 88
Liquids are similar to gases because (a) both possess the property of flowing and take the volume of the containers (b) both diffuse and take the shape of the containers (c) both are readily compressible and diffuse (d) both are capable of infinite expansion.
Problem 89
Which of the following does not decrease with rise in temperature? (a) Density (b) Surface tension (c) Vapour pressure (d) Viscosity
Problem 90
Vapour pressure of a liquid increases with (a) decrease in temperature (b) increase in temperature (c) increase in surface area (d) increase in volume.
