Chemistry MCQs Test P 18

Kp and Kc Relationship and Characteristics of K

1. What will be the value of Kp if the Kc is 26 for a reaction, PCl5 ⇌ PCl3 + Cl2 at 25o°?

1. 0.57
2. 0.46
3. 0.83
4. 0.61

Answer: (d)

2. For which of the following reactions Kp is less than Kc?

1. 2HI ⇌ H2 + I2
2. N2 + O2 ⇌ 2NO
3. N2O4 ⇌ 2NO2
4. 2SO2 + O2 ⇌ 2SO3

Answer: (d)

3. Two moles of PCl5 were heated to 400oC in 2 litres closed vessel. At equilibrium, 40% of PCl5 was dissociated into PCl3 and Cl2. Its Kc will be

1. 3.75 mol/L
2. 0.533 mol/L
3. 0.267 mol/L
4. None of the above

Answer: (c)

4. Which of the following is not correct?

1. large value of K indicates large amount of products
2. small value of K indicates large amount of reactants
3. for K < 1 amount of reactants > amount of products
4. none of the above

Answer: (d)

5. When Q (concentration quotient) is smaller than equilibrium constant

1. reaction will be in equilibrium
2. reaction will proceed in forward direction
3. reaction will proceed in backward direction
4. none of the above

Answer: (b)

6. If Kp and Kc are in equilibrium constants in terms of partial pressure and concentration

1. Kp = Kc/RT
2. Kp = KcRT
3. Kp = Kc/(RT)𐤃n
4. Kp = Kc(RT)𐤃n

Answer: (d)

7. For a reaction in equilibrium

1. Q (concentration quotient) = K (equilibrium constant)
2. Q > K
3. Q < K
4. none of the above

Answer: (a)

8. Active mass in the law of mass action is

1. molar concentration
2. absolute concentration
3. concentration at 0oC
4. molar mass

Answer: (a)

9. The mass of a gas dissolved in a given mass of a solvent at any temperature is directly proportional to

1. pressure of gas
2. volume of gas
3. density of gas
4. none of above

Answer: (a)

10. Which of the following is an example of solid-solution equilibrium?

1. dissolution of sugar in water
2. melting of ice
3. evaporation of water in a closed vessel
4. none of the above

Answer: (a)

Electrical Conductors Arrhenius Theory and Ostwalds Dilution Law

1. If a conductor length is increased, 100% then keeping all other parameters fixed, what will be the increase in power dissipate?

1. 100%
2. 200%
3. 300%
4. 400%

Answer:(b)

2. What happens to the conductivity of semiconductors when there is an increase in temperature?

1. decrease
2. increase
3. first, increase and then decrease
4. remains constant

Answer:(b)

3. Semiconductors have electrical conductivity

1. more than metals but less than insulators
2. less than thermistor but more than an insulator
3. equal to the thermistor
4. less than metals but more than typical insulators

Answer:(d)

4. When temperature increases the conductance of conductors is

1. decrease
2. increase
3. first, increase and then decrease
4. remains constant

Answer:(a)

5. When acids dissolve in water it releases

1. H+ ion
2. H– ion
3. H3O+ ion
4. H3O2+ ion

Answer:(a)

6. Which element is always present in Arrhenius acid

1. oxygen
2. nitrogen
3. hydrogen
4. none of the above

Answer:(c)

7. Ostwald’s dilution law is applicable to

1. strong electrolytes only
2. weak electrolytes only
3. non-electrolytes
4. strong as well as weak electrolytes

Answer:(b)

8. In the titration of iodine against hype the indicator used is

1. starch
2. potassium ferricyanide
3. methyl orange
4. methyl red

Answer:(a)

9. One litre of 0.5M KCl solution is electrolysed for one minute in a current of 16.08 mA. Considering 100% efficiency, the pH of the resulting solution will be

1. 7
2. 9
3. 8
4. 10

Answer:(c)

Hydrogen Ion Concentration pH Scale and Buffer Solution

1. Range of pH scale is

1. 7 to 10
2. 0 to 10
3. 0 to 14
4. 7 to 14

Answer: (c)

2. Level of pH found in antacid solution

1. ≤ 6.5
2. ≥ 7.0
3. > 10
4. > 14

Answer: (b)

3. Three unknown solutions are given with pH value of 6, 8 & 9.5 respectively. Which solution will contain the maximum OH– ion?

1. Solution sample-1
2. Solution sample-2
3. Solution sample-3
4. Data are insufficient

Answer: (c)

4. pH of neutral salt is

1. 7
2. <7
3. >7
4. 0

Answer: (a)

5. Ammonium sulphate salt is

1. basic salt
2. acidic salt
3. neutral salt
4. complex salt

Answer: (a)

6. When sulphuric acid reacts with eggshell it produces

1. hydrogen gas
2. nitrogen gas
3. carbon monoxide
4. carbon dioxide gas

Answer: (d)

7. In the Chlor-alkali process, the byproduct gases are

1. hydrogen only
2. hydrogen and oxygen gas
3. hydrogen and chlorine gas
4. chlorine and nitrogen gas

Answer: (c)

8. The following salt is not hygroscopic in nature

1. NaCl
2. MgCl
3. CaCl2
4. KCl

Answer: (a)

9. When more and more water is diluted with acids its H+ ion concentration will

1. increase
2. decrease
3. remains the same
4. depends on the type of acids

Answer: (b)

10. When acids react with metal oxide it produces

1. water and salt
2. salts and hydrogen gas
3. salts only
4. no reaction takes place

Answer: (a)

2nd and 3rd Law of Thermodynamics and Entropy

1. Which of the following processes is used to do maximum work done on the ideal gas that is compressed to half of its initial volume?

1. isothermal
2. isochoric
3. isobaric
4. adiabatic

Answer: (d)

2. What is the ratio of Cp/Cv for gas if the pressure of the gas is proportional to the cube of its temperature and the process is an adiabatic process?

1. 2
2. 3/2
3. 4/3
4. 5/3

Answer: (b)

3. The coefficient performance of a refrigerator is 5. Calculate the heat rejected to the surrounding if the temperature inside the freezer is -20oC

1. 11oC
2. 41oC
3. 21oC
4. 31oC

Answer: (d)

4. What is a necessary condition for a reaction to be spontaneous at all temperatures?

1. 𐤃H < 𐤃G
2. 𐤃G and H should be positive
3. 𐤃H = 𐤃G = 0
4. 𐤃G and 𐤃H should be negative

Answer: (d)

5. Which of the following factor affects the heat of reaction based on Kirchhoff equation?

1. molecularity
2. temperature
3. pressure
4. volume

Answer: (b)

6. Chemical dissociation is

1. exothermic
2. reversible
3. endothermic
4. reversible and endothermic

Answer: (d)

7. Which of the following is the largest unit of energy?

1. electron volt
2. joule
3. calorie
4. erg

Answer: (c)

8. A perfect black body has a unique characteristic feature as

1. a good absorber only
2. a good radiator
3. a good absorber and a good radiator
4. neither a radiator nor an absorber

Answer: (c)

9. A thermodynamic process where no heat is exchanged with the surroundings is

1. isothermal
2. adiabatic
3. isobaric
4. isotropic

Answer: (b)

10. Which of the following laws was formulated by Nernst?

1. First law of thermodynamics
2. Second law of thermodynamics
3. Third law of thermodynamics
4. None of the above

Answer: (c)

Half Life

1. How many milligrams of tritium will remain after 49.2 years if the starting amount is 32 mg? The half-life of tritium is 12.3 years.

(a) 8 mg

(b) 2 mg

(c) 1 mg

(d) 4 mg

2. Find the half-life of 614C if 𝝺 is 2.31 x 10-4.

(a) 4 x 103 years

(b) 3 x 103 years

(c) 3.5 x 104 years

(d) 2 x 102 years

3. 200 mg of 14C will become 25 mg in how many years if the half-life is 5760 years?

(a) 5760 years

(b) 17280 years

(c) 23040 years

(d) 11520 years

4. If a body requires 0.01 m activity of radioactive substance (half-life = 6 hrs) after 24 hrs of injection then what is the maximum activity of injection to be injected?

(a) 0.04

(b) 0.32

(c) 0.16

(d) 0.08

5. What would be the remaining concentration of 300 g of radioactive substance after 18 hours if the half-life is 3 hours?

(a) 9.37 g

(b) 2.34 g

(c) 3.34 g

(d) 4.68 g

6. What would be the remaining concentration of 1 g of radioactive substance after 400 days if the half-life is 100 days?

(a) 1/16

(b) 1/4

(c) 1/2

(d) 1/8

7. What would be the remaining concentration of 10.4 micrograms of 231Pa after 3.25 x 105 years if the half-life is 3.25 x 104 years?

(a) 0.0240 micrograms

(b) 2.18 micrograms

(c) 1.4 micrograms

(d) 0.0102 micrograms

8. The radioactive isotope of phosphorus, P-32 is used as a tracer in the liver. If 3.5 mg is left in a sample after 288 hrs then how much P-32 was administered initially? [Half-life of P-32 is 14.3 days]

(a) 7 mg

(b) 6.26 mg

(c) 1.96 mg

(d) 4.17 mg

9. Uranium-238 forms thorium-234 after radioactive decay and has a half-life of 4.5 x 109 years. How many years will it take to decay 75% of the initial amount?

(a) 4.5 x 109 years

(b) 9 x 1010 years

(c) 4.5 x 1010 years

(d) 9 x 109 years

10. Which of the following radiations is the most penetrating?

(a) 𝞬

(b) 𝜶

(c) 𝜷

(d) neutron

Answer

1. (b)	2. (b)	3. (b)	4. (c)	5. (d)
6. (a)	7. (d)	8. (b)	9. (d)	10. (a)

Alkane and Alkene

1. Which of the following conformation of n-butane is the most stable?

(a) eclipsed

(b) gauche

(c) staggered

(d) skew boat

2. Find the correct order for relative energies of the ethane conformations

(a) staggered < skewed < eclipsed

(b) skewed < staggered < eclipsed

(c) skewed < eclipsed < staggered

(d) staggered < eclipsed < skewed

3. Find the alkane (C5H12), which will give only one type of monohalogenated compound

(a) 2,2-dimethylpropane

(b) 2-methylbutane

(c) cyclopentane

(d) n-pentane

4. The bond angle between H-C-C bonds in ethane is

(a) 120°

(b) 180°

(c) 109°

(d) 109.5°

5. Alkanes undergo halogenation. It is an example of

(a) nucleophilic substitution

(b) elimination

(c) free-radical substitution

(d) electrophilic substitution

6. Which of the following is the most volatile compound?

(a) n-pentane

(b) Isobutane

(c) 2-methyl butane

(d) 2, 2-dimethyl propane

7. Paraffin wax is

(a) Saturated hydrocarbons

(b) Unsaturated hydrocarbons

(c) Alcohol

(d) Ester

8. Find the correct order for the ease of formation of free radicals

(a) 1° > 2° > 3°

(b) 3° > 2° > 1°

(c) 2° > 1° > 3°

(d) 2° > 3° > 1°

9. Formation of an alkane from the reduction of an alkyl halide with Zn is known as

(a) Cannizzaro reaction

(b) Frankland reaction

(c) Kolbe reaction

(d) Wurtz reaction

10. Find the compound with the highest boiling point among the following

(a) n-Butane

(b) n-Octane

(c) Iso-octane

(d) 2,2,3,3-Tetramethylbutane

Answer

1. (c)	2. (a)	3. (a)	4. (d)	5. (c)
6. (d)	7. (a)	8. (b)	9. (b)	10. (b)

11. Which of the following compounds react most readily with Br(g)?

(a) C2H2

(b) C3H6

(c) C2H4

(d) C4H10

12. When propene reacts with HBr in the presence of peroxide, it gives rise to

(a) allyl bromide

(b) isopropyl bromide

(c) n-propyl bromide

(d) 3-bromopropane

13. Find the alkene with maximum stability

(a) cis-2-Butene

(b) trans-2-Butene

(c) 1-Butene

(d) All have the same stability

14. Ethylene bromide on treatment with Zn gives

(a) Alkyne

(b) Alkene

(c) Alkane

(d) All of the above

15. Which of the following reactions is common in alkenes?

(a) Addition

(b) Elimination

(c) Substitution

(d) Superposition

16. Cis-trans isomerism in alkenes is due to

(a) chiral carbon

(b) free rotation about single bond

(c) free rotation about the double bond

(d) restricted rotation about the double bond

17. Baeyer’s reagent is used to detect

(a) glucose

(b) double bonds

(c) oxidation

(d) reduction

18. Which of the following will form 2 acetaldehyde molecules on ozonolysis?

(a) 1-pentene

(b) 2-pentene

(c) 1-butene

(d) 2-butene

19. Which of the following reagents will form 1-propanol from propene?

(a) B2H6, H2O2, OH–

(b) Aq. KOH

(c) H2O, H2SO4

(d) Hg(OAc)2, NaBH4/H2O

20. Geometrical isomerism is exhibited by

(a) 2-Butene

(b) 2-Butyne

(c) 2-Butenol

(d) Butanol

Answer

11. (b)	12. (c)	13. (b)	14. (b)	15. (a)
16. (d)	17. (b)	18. (d)	19. (a)	20. (a)