Untitled Document

Question Bank No: 2

1. The activation energy of a reaction can be determined by

a)		changing the concentration of reactants
b)		evaluating rate constant at standard temperature
c)		evaluating rate constant at two different temperatures
d)		by doubling conc. of reactants

2. For a first order reaction, the plot of log k against 1/T is a straight line. The slope of the line is equal to

a)		$\frac{E_{a}}{R}$
b)		$\frac{2.303}{E_{a} \times R}$
c)		$\frac{E_{a}}{2.303}$
d)		$\frac{- E_{a}}{2.303 R}$

3. Effect of temperature on reaction rate is given by

a)		Claisen-Clapeyron equation
b)		Arrhenius equation
c)		Gibbs-Helmholtz equation
d)		Kirchoff's equation

4. Given $t_{\frac{1}{2}}$ =3hr. Then how many grm of a substance will remain after 18th hr from 300 gram of a substance

a)		4.6 gm
b)		5.6 gm
c)		9.2 gm
d)		6.4 gm

5. A reaction is 50% complete in 2 hours and 75% complete in 4 hours the order of reaction is

a)		0
b)		1
c)		2
d)		3

6. A first order reaction is 75% complete after 32 minutes. When was 50% of the reaction completed?

a)		16 minutes
b)		8 minutes
c)		4 minutes
d)		32 minutes

7. For a zero order reaction A $\to P, t_{\frac{1}{2}}$ is (k is rate constant)

a)		$\frac{{[A]}_{0}}{2 k}$
b)		$\frac{In 2}{k}$
c)		$\frac{1}{k [A]_{0}}$
d)		$\frac{In 2}{[A]_{0} k}$

8. The hydrolysis of ester in alkaline medium is a

a)		1st order reaction with molecularity 1
b)		2nd order reaction with molecularity 2
c)		1st order reaction with molecularity 2
d)		2nd order reaction with molecularity 1

9. In a first reaction, 75% of the reactants disappeared in 1.386 hr. What is the rate constant?

a)		3.6 $\times 10^{- 3} s^{- 1}$
b)		2.7 $\times 10^{- 4} s^{- 1}$
c)		72 $\times 10^{- 3} s^{- 1}$
d)		1.8 $\times 10^{- 3} s^{- 1}$

10. The rate of reaction, A + B $\to$ Products is given by the equation r=k [A] [B]. If b is taken in large excess, the order of the reaction would be

a)		2
b)		1
c)		0
d)		unpredictable

11. An example of autocatalytic reaction is

a)		the decomposition of nitroglycerine
b)		thermal decomposition of KCl $O_{3}$ and Mn $O_{2}$ mixture
c)		Breakdown of ${{}^{14}C}_{6}$
d)		hydrogenation of vegetable oil using nickel catalysts

12. Mark the correct statement. In a reversible reaction

a)		the catalyst catalyses the forward reaction
b)		the catalyst catalyses the backward reaction
c)		the catalyst influences the direct and the reverse reaction to the same extent
d)		the catalyst increases the rate of forward reaction and decreases the rate of backward reaction

13. The second order rate constant is usually expressed as

a)		mol litre $\sec^{- 1}$
b)		${mol}^{- 1} {litre}^{- 1} \sec^{- 1}$
c)		mol ${litre}^{- 1} \sec^{- 1}$
d)		${mol}^{- 1} litre \sec^{- 1}$

14. The rate at which a substance reacts depends on its

a)		atomic weight
b)		equivalent weight
c)		molecular weight
d)		active mass

15. The rate constant of a reaction depends on

a)		temperature
b)		mass
c)		weight
d)		time

16. The rate constant is given by the equation K=pz $e^{- \frac{E}{RT}}$ . Which factor should register a decrease for the reaction to proceed more rapidly?

a)		T
b)		Z
c)		E
d)		P

17. For the reaction $H_{2} + {Cl}_{2} ⟶_{}^{sunlight}$ 2 $HCl$ taking place on water, the order of reation is

a)		0
b)		1
c)		2
d)		3

18. Heat of neutralisation of strong acid against strong base is constant and is equal to

a)		-13.7 kcal
b)		-57 kJ
c)		$- 5.7 \times 10^{4} J$
d)		all of the above

19. In which of the following neutralisation reaction, the heat of neutralisation will be highest.

a)		${NH}_{4} OH$ and $H_{2} {SO}_{4}$
b)		$HCl$ and $NaOH$
c)		${CH}_{3} COOH$ and KOH
d)		${CH}_{3} COOH$ and ${NH}_{4} OH$

20. The heat of formation of $CO$ and ${CO}_{2}$ are -26.4 kcal and -94 kcal respectively. Heat of combustion of CO will be

a)		26.4 kcal
b)		-67.6 kcal
c)		-120.6 kcal
d)		+52.8

21. If the enthalpy of vapourisation of water is 186.5 J ${mol}^{- 1},$ the entropy of its vapourisation will be

a)		$0.5 J K^{- 1} {mol}^{- 1}$
b)		$1.0 J K^{- 1} {mol}^{- 1}$
c)		1.5 $J K^{- 1} {mol}^{- 1}$
d)		2.0 $J K^{- 1} {mol}^{- 1}$

22. In general, for exothermic reactions to be spontaneous

a)		temperature should be high
b)		temperature should be zero
c)		temperature should be low
d)		temperature has no effect

23. For a reaction to occur spontaneously

a)		$(Δ H - T Δ S)$ must be negative
b)		$(Δ H + T Δ S) must be negative$
c)		$Δ H$ must be negative
d)		$Δ S$ must be negative

24. Enthalpy of reaction $Δ H$ is represented as

a)		$Δ H = Σ H_{P} - Σ H_{R}$
b)		$Δ H = d H_{P} + d H_{R}$
c)		$Δ H = \frac{{dH}_{p}}{{dH}_{R}}$
d)		$Δ H = \frac{Σ H_{P}}{{dH}_{R}}$

25. $S + \frac{3}{2} O_{2} \to {SO}_{3} + 2 x kcal ... (1)$
${SO}_{2} + \frac{1}{2} O_{2} \to {SO}_{3} + y kcal ..... (2)$
Find out the heat of formation of ${SO}_{2}$

a)		$2 x - y$
b)		$2 x + y$
c)		$x + y$
d)		$\frac{2 x}{y}$

26. 1 mole of an ideal gas 300 K is expanded isothermally from an initial volume of 1L to 10 L. The $Δ E$ for this process is (R=2 cal. $K^{- 1} {mol}^{- 1})$

a)		163.7 cal
b)		1381.1 cal
c)		9 lit atm
d)		zero

27. The reaction is spontaneous, if the cell potential is

a)		positive
b)		negative
c)		zero
d)		infinity

28. For a melting of a solid at $25^{0} C$ , the fusion process requires energy equivalent to 2906 J to be added to system considering the process to be reversible at fusion point, the entropy change for the process is

a)		9.75 J $K^{- 1}$
b)		11.272 J $K^{- 1}$
c)		2.33 J $K^{- 1}$
d)		Insufficient data