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Question Bank No: 2

1. A reaction is not feasible, if

a)		$Δ H$ is positive and $Δ S$ is also positive
b)		$Δ H$ is positive and $Δ S$ is negative
c)		$Δ H$ is negative and $Δ S$ is also negative
d)		$Δ H$ is negative and $Δ S$ is positive

2. When enthalpy and entropy change for a chemical reaction are - 2.5 $\times 1 0^{3}$ cals and 7.4 cals deg -1 respectively. Predict that reaction at 298 K is

a)		Spontaneous
b)		reversible
c)		irreversible
d)		non - spontaneous

3. Consider the following reaction occuring in a automobile engine 2 $C_{8} H_{18} (g) + 25 O_{2} (g) \to 16 C O_{2} (g) + 18 H_{2} O (g)$
the signs of $Δ H, Δ S$ and $Δ G$ for above reaction would be

a)		+, -, +
b)		-, +, -
c)		-, +, +
d)		+, +, -

4. Which of the following is true for reaction $H_{2} O (1) ⇌$ $H_{2} O (g)$ at 10 $0^{\circ} C, 1$ atm. Pressure

a)		$Δ H = Δ E$
b)		$Δ E = 0$
c)		$Δ H = 0$
d)		$Δ H = T Δ S$

5. All the naturally occuring processes proceed spontaneously in a direction which leads to

a)		decrease of entropy
b)		increase of entropy
c)		increase of free energy
d)		decrease of free energy

6. A reaction, A + B $\to$ C + D +q, is found to have a positive entropy change, the reaction will be

a)		Possible at high temperature
b)		Possible only at low temperature
c)		Not Possible at any temperature
d)		Possible at any temperature

7. A particular reaction at $27^{o} C$ for which $Δ H > 0 and Δ S > 0$ is formed to be non-spontaneous. The reation may proceed spontaneously if

a)		the temperature is decreased
b)		the temperature id increased
c)		the temperature is kept constant
d)		it is carried in open an vessel at $27^{o} C$

8. The sign of $Δ G$ for the process of melting of ice at 273 K and 1 atm pressure is

a)		positive
b)		negative
c)		neither positive nor negative
d)		either positive or negative

9. Which thermodynamic property provides a measure of randomness in the system ?

a)		enthalpy
b)		PV- work
c)		free energy
d)		entropy

10. Which of the following has highest entropy?

a)		water
b)		graphite
c)		mercury
d)		hydrogen

11. According to third law of thermodynamic, the entropy at 0 K is zero for

a)		elements in their stable form
b)		perfectly crystalline solids
c)		substance at 1 atm and 2 $5^{o} C$
d)		$N_{2} O$

12. In a reversible process, $Δ S_{sys} + Δ S_{surr}$ is

a)		> 0
b)		< 0
c)		$\geq 0$
d)		= 0

13. When the egg is hard boiled, there is

a)		increase in disorder
b)		decrease in disorder
c)		no change in disorder
d)		$Δ G$ is negative

14. Which of the following process has negative value of $Δ S ?$

a)		dissolution of sugar in water
b)		stretching of rubber band
c)		decomposition of lime stone
d)		evaporation of water

15. The enthalpy of combustion of a substance

a)		is always positive
b)		is always negative
c)		can be either or greater than zero
d)		is unpredictable till calculation are done

16. $N_{2} (g)$ +2 $O_{2} (g) - 2 N O_{2} + X kJ$
2NO(g)+ $O_{2} (g) -$ $2 N O_{2} (g) + Y kJ$ . The enthalpy of formation of NO is

a)		(2X-2Y)
b)		X-Y
c)		$\frac{1}{2}$ (Y-X)
d)		$\frac{1}{2}$ (X-Y)

17. The difference between $Δ H and Δ E$ at constant volume is equal to

a)		R
b)		p $Δ V$
c)		V $Δ p$
d)		$\frac{3}{2} R$

18. For the reaction 2N $H_{3} (g) \to N_{2} (g) + 3 H_{2} (g)$ , which of the following statement is correct?

a)		$Δ H = Δ E$
b)		$Δ H \geq Δ E$
c)		$Δ H > Δ E$
d)		$Δ H = 0$

19. The heat of combustion of benzene determined in a bomb calorimeter is -870 K cal ${mol}^{- 1}$ at 298K. The value of $Δ E$ for the reaction is

a)		-1740kcal ${mol}^{- 1}$
b)		+870 kcal ${mol}^{- 1}$
c)		-870 kcal ${mol}^{- 1}$
d)		+1740 kcal ${mol}^{- 1}$

20. When ammonium chloride is dissolved in water, the solution becomes cold. The change is

a)		endothermic
b)		exothermic
c)		super cooling
d)		none of the above

21. The internal energy of one mole of a gas is

a)		$\frac{3}{2}$ RT
b)		$\frac{1}{2}$ kT
c)		$\frac{1}{2}$ RT
d)		$\frac{3}{2}$ kT

22. A thermally isolated gaseous system can exchange energy with the surroundings. The mode of transference of energy can be

a)		heat
b)		work
c)		heat and radiation
d)		only radiation

23. For the process to occur under adiabatic conditions

a)		$Δ T = 0$
b)		$δ Q = 0$
c)		$Δ P = 0$
d)		$δ W = 0$

24. Which of the following is an internsive property?

a)		volume
b)		mass
c)		density
d)		energy

25. Which among the following state functions is an extensive property of the system?

a)		temperature
b)		volume
c)		refractive index
d)		viscosity

26. A cup of tea placed in the room eventually acquires a room temperature by losing heat. The process may be considered close to

a)		cyclic process
b)		reversible process
c)		isothermal process
d)		none of these

27. The difference between $Δ H$ and $Δ E$ for the combustion of methane at $27^{0} C$ will be

a)		$8.314 \times 27 \times (- 3)$
b)		$8.314 \times 300 \times (- 3)$
c)		$8.314 \times 300 \times (- 2)$
d)		$8.314 \times 300 \times 1$

28. According to the second law of thermodynamics, a process is spontaneous, if

a)		$Δ S$ universe >0
b)		$Δ S universe = 0$
c)		$Δ H$ system > 0
d)		$Δ S universe < 0$

29. The law of thermodynamics that provides the basis for the determination of absolute entropy of a substance is

a)		zeroth law
b)		first law
c)		second law
d)		third law

30. When one mole of a gas is heated at constant volume, temperature is raised from 298 to 308 K. Heat supplied to gas is 500 J. Then which statement is correct?

a)		q = W=500 J, $Δ U = 0$
b)		q= $Δ U = 500 J, W = 0$
c)		q=W=500 J, $Δ U = 500$
d)		$Δ U = 0, q = W = - 500 J$

31. The heat required to raise the temperature of a body by 1 K is called

a)		specific heat
b)		thermal capacity
c)		water equivalent
d)		none of these

32. If an endothermic reaction is non spontaneous at freezing point of water and becomes feasible at its boiling point, then

a)		$Δ H$ is negative, $Δ S$ is negative
b)		$Δ H$ and $Δ S$ both are positive
c)		$Δ H$ and $Δ S$ both are negative
d)		$Δ H$ is positive and $Δ S$ is negative

33. The intensive property among the following is

a)		mass
b)		volume
c)		enthalpy
d)		$\frac{mass}{volume}$

34. The enthalpy of formation of ammonia is -46.2 kJ ${mol}^{- 1}$ . The enthalpy change for the reaction $2 {NH}_{3} \to N_{2} + 3 H_{2} is$

a)		42 kJ
b)		64 kJ
c)		80 kJ
d)		92 kJ