7/30/2019 Full test 03

1/4

SCHOOL OF MATHEMATICS AND SCIENCE A World of Numbers and Logic

Visit Us at: www.somas.in mail us: sms@somas.in contact: 0674 2531733

Full test 03 Time:03:00 hrs

In this question set, there are three sections (Physics, Mathematics &

Chemistry).

Answer all the questions.

Marking scheme is written in each section.

GOODLUCK

ChemistrySect ion A (Single Answ ers correct) [20 (+4/1)]

1. Total number of orbitals containing electrons in Cr (24) atom in its ground

state is:

a. 15 b. 13 c. 12 d. None of these

2. The voltage with which an electron has to be accelerated so as to have its

wavelength equal to 1 isa. 10 V b. 150 V c. 15 V d. 1 V

3. If Z-component of orbital angular momentum is , then the magnitudeof orbital angular momentum can never be

a. b.

c.

d. both a and b

4. A mixture of C2H2 and C3H8 occupied a certain volume at 80 mm Hg. The

mixture was completely burnt to CO2 and H2O(I). When the pressure of CO2

was found to be 42.5 mm Hg at the same temperature and volume, the

fraction of C2H2 in mixture is

a. 0.125 b. 0.5 c. 0.6 d. 0.8

5. A definite amount of gaseous hydrocarbon having (carbon atoms less than 5)

was burned with sufficient amount of O2. The volume of all reactants was 600

ml, after the explosion the volume of the products (CO2(g) and H2O(g)) was

found to be 700 ml under the similar conditions. The molecular formula of the

compound is

a. C3H8 b. C3H6 c. C3H4 d. C4H10

6. For the reaction

2A(g) + B(g) 3C(g)Where A and B gases are insoluble in water and C forms a basic solution in it.If we started with 3 moles of A and 2 moles of B are allowed to react in 50 L

flask at 500 K, after the formation of C, 50 litre of the water is added to the

flask and due to this addition of water the temperature is reduced to 200 K. At

this point the pressure inside the flask will be

a. 0.1642 atm b. 0.3 atm c. 0.469 atm d. 0.0016 atm

7/30/2019 Full test 03

2/4

Full test 03

SCHOOL OF MATHEMATICS AND SCIENCE A World of Numbers and Logic

Visit Us at: www.somas.in mail us: sms@somas.in contact: 0674-2531733

7. One litre of a gaseous mixture (CH4 and H2) effuses in 5 minute and 11

seconds while one litre of O2 takes 10 minutes. The molar ratio of CH4 : H2 is

a. 47 : 53 b. 50 : 50 c. 53 : 47 d. 32 : 68

8. For the chemical reaction

3A(g) + 4B(g) 5C(g) + 50 kJThe amount of C at equilibrium is affected bya. Temperature and pressure b. Temperature only

c. Pressure only d. None

9. For the reaction

CO2(g) + H2(g) CO(g) + H2O(g)The Kp for the reaction is 0.21 at 700 K.

If the reaction was started with 0.34 moles of CO2 and 0.34 moles of H2 at 700

K, the concentration of CO2 when equilibrium is attained, is

a. 0.52 M b. 0.17 M c. 0.34 M d. 0.26 M

10. 0.96g of HI was heated to 720 K till the equilibrium. It was then cooled quickly

and the % dissociation of HI was found to be 21 %. The volume of hypo

required for the liberated I2 is

a. 10 ml 0.1 N Na2S2O3 b. 20 ml 0.02 N NaS2O3

d. 6 ml 0.3 M NaS2O3 d. 10 ml 0.2 M NaS2O3

11. At 200 C PCl5 dissociates as follows:PCl5(g) PCl3(g) + Cl2(g)It was found that the equilibrium vapours are 62 times as heavy as hydrogen.

The degree of dissociation of PCl5 at 200 C isa. 10 % b. 42 % c. 50 % d. 68 %

12. A certain weak acid has a dissociation constant of 1 x 10-4. The equilibrium

constant for its reaction with a strong base is

a. 1 x 10-4 b. 1 x 10-10 c. 1 x 1010 d. 1 x 10-14

13. 0.1 M acetic acid solution is titrated against 0.1 M NaOH solution. What would

be the difference in pH between and stages of neutralization of acid?

a. 2 log b. 2 log c. log 1/3 d. 2 log 3

14. The pKa of acetylsalicylic acid (aspirin) is 3.5. The pH of gastric juice in human

stomach is about 2-3 and the pH in the small intestine is about 8. Aspirin will

bea. Unionised in the small intestine and in the stomach

b. Completely ionized in the small intestine and in the stomach

c. Ionised in the stomach and almost unionized in the small intestine

d. Ionised in the small intestine and almost unionside in the stomach

15. The ionization constant of NH4+ in water is 5.6 x 10-10 at 25 C. The rate

constant for the reaction of NH4+ and OH- to from NH3 and H2O at 25 C is 3.4

x 1010 L mol- S-1. The rate constant for proton transfer from water to NH3 is

a. 6.07 x 105 S-1 b. 6.07 x 1010 S-1

c. 6.07 x 10-5 S-1 d. 6.07 x 10-10 S-1

7/30/2019 Full test 03

3/4

Full test 03

SCHOOL OF MATHEMATICS AND SCIENCE A World of Numbers and Logic

Visit Us at: www.somas.in mail us: sms@somas.in contact: 0674-2531733

16. The hydrated salt Na2SO4. nH2O undergoes 55.9 % loss in weight on heating

and becomes anhydrous. The value of n will be

a. 5 b. 7 c. 9 d. 10

17. 4.617 x 10-3 moles of NaNO3 require 4.04 moles of reducing agent to get

reduced to NH3. What is the n-factor of the reducing agent.a. 5 b. 6 c. 7 d. 8

18. If S + O2 SO2; H = 298.2 kJSO2 + O2 SO3; H = 98.7 kJSO3 + H2O H2SO4; H = 130.2 kJH2 + O2 H2O; H = 227.3 kJThe enthalpy of formation of H2SO4 at 298 K will be

a. 754.4 kJ b. +320.5 kJ c. 650.3 kJ d. 433.7 kJ

19. The difference between heat of reaction at constant pressure and constant

volume for the reaction given below at 25 C in kJ is2C6H6(I) + 15O2(g) 12CO2(g) + 6H2O(I)a. 7.43 b. + 3.72 c. 3.72 d. 7.43

20. A mixture of 2 moles of CO and 1 mole of O2 in a closed vessel is ignited to

convert to CO in to CO2 then

a. H = Eb. H > Ec. H < Ed. The relation dependents upon the capacity of the vessel

Section B (Integer Answers Type) [10 (+4)]

21. 2MgCO3 MgO + CO2 Mg(OH)2 MgSO4(4.2 g)

Then weight of MgSO4 will be formed in this series is ___________

22. An electron jumps from 3rd energy level of hydrogen atoms to ground state

and emits radiation. Ten photons of such radiation are absorbed by a

dispositive lithium ion and the electron jumps to x energy level. What is the

value of x? ________

23. In the Bohr orbits if the mass of electrons is doubled, the radius will becomes

x times of original, keeping velocity constant. What is the value of x? ______

24. 20 L air at 50 C has 90 % relative humidity has been cooled to 25 C where ithas 20 % relative humidity. What is the new pressure of air if it was originally

present at 4.57 atm? ____________

Aq. tension at 50 C = 0.5 atmAq. tension at 25 C = 0.1 atm

25. For a given reaction, where K is the equilibrium constant,

InK =( )

then S for the reaction is (in cal mol-1) ___________

7/30/2019 Full test 03

4/4

Full test 03

SCHOOL OF MATHEMATICS AND SCIENCE A World of Numbers and Logic

Visit Us at: www.somas.in mail us: sms@somas.in contact: 0674-2531733

26. The heat of neutralization of 0.1 mol HF with 0.1 mole NaOH is 5.91 kJ. If the

enthalpy of ionization of HF is 2 kJ mol-1. What is the heat of hydration of F-

ions in kJ mol-1? ________________

27. A weak acid (analyte) titrated against strong base (titrant). At half of

equivalence point pH is x. 10 times dilution is made for that solution then pHof the solution will be x y, then y will be _____________28. Ionization constant of benzoic acid is 6.46 x 10-5 and Ksp of silver benzoate is

2.5 x 10-13. How many times the salt is more soluble in buffer of pH of 5.59 as

compared to solubility in pure water? ___________

29. What is the oxidation state of chromium in chromic acid? ___________

30. NO N2O+ NO2In this reaction equivalent weight of NO is xM/y, where M is the molar mass of

NO, then x + y will be __________