#### Important 1mark -chapter 9,10

11th Standard

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Chemistry

Use blue pen Only

Time : 00:50:00 Hrs
Total Marks : 30

30 x 1 = 30
1. Stomach acid, a dilute solution of HCl can be neutralised by reaction with Aluminium hydroxide
Al (OH)3 + 3HCl (aq) → AlCl3 + 3 H2O
How many millilitres of 0.1 M Al(OH)3 solution are needed to neutralise 21 mL of 0.1 M HCl?

(a)

14 mL

(b)

7 mL

(c)

21 mL

(d)

none of these

2. The partial pressure of nitrogen in air is 0.76 atm and its Henry's law constant is 7.6 × 104 atm at 300K. What is the mole fraction of nitrogen gas in the solution obtained when air is bubbled through water at 300K?

(a)

1 x 10-4

(b)

1 x 10-6

(c)

2 x 10-5

(d)

1 x 10-5

3. Which one of the following is incorrect for ideal solution?

(a)

$\Delta H_{mix}=0$

(b)

$\Delta U_{mix}=0$

(c)

$\Delta P=P_{observed}-P_{calculated\ by\ raoults\ law}=0$

(d)

$\Delta G_{mix}=0$

4. Which one of the following gases has the lowest value of Henry's law constant?

(a)

N2

(b)

He

(c)

CO2

(d)

H2

5. P1 and P2 are the vapour pressures of pure liquid components, 1 and 2 respectively of an ideal binary solution if x1 represents the mole fraction of component 1, the total pressure of the solution formed by 1 and 2 will be

(a)

P1 + x1 (P2 – P1)

(b)

P2 – x1 (P2 + P1)

(c)

P1 – x2 (P1 – P2)

(d)

P1 + x2 (P1 – P2)

6. Osometic pressure (p) of a solution is given by the relatio

(a)

$\pi$ = nRT

(b)

$\pi$V = nRT

(c)

$\pi$RT = n

(d)

none of these

7. Which one of the following binary liquid mixtures exhibits positive deviation from Raoults law?

(a)

Acetone + chloroform

(b)

Water + nitric acid

(c)

HCl + water

(d)

ethanol + water

8. The Henry's law constants for two gases A and B are x and y respectively. The ratio of mole fractions of A to B is 0.2. The ratio of mole fraction of B and A dissolved in water will be

(a)

${2x\over y}$

(b)

${y\over 0.2x}$

(c)

${0.2x\over y}$

(d)

${5x\over y}$

9. The empirical formula of a nonelectrolyte(X) is CH2O. A solution containing six gram of X exerts the same osmotic pressure as that of 0.025 M glucose solution at the same temperature. The molecular formula of X is

(a)

C2H4O2

(b)

C8H16O8

(c)

C4H8O4

(d)

CH2O

10. Two liquids X and Y on mixing gives a warm solution. The solution is

(a)

ideal

(b)

non-ideal and shows positive deviation from Raoults law

(c)

ideal and shows negative deviation from Raoults Law

(d)

non-ideal and shows negative deviation from Raoults Law

11. The mass of a non-voltaile solute (molar mass 80 g mol–1) which should be dissolved in 92g of toluene to reduce its vapour pressure to 90%

(a)

10g

(b)

20g

(c)

9.2g

(d)

8.89g

12. The Van't Hoff factor (i) for a dilute aqueous solution of the strong elecrolyte barium hydroxide is

(a)

0

(b)

1

(c)

2

(d)

3

13. Which of the following aqueous solutions has the highest boiling point?

(a)

0.1 M KNO3

(b)

0.1 M Na3PO4

(c)

0.1 BaCl2

(d)

0.1 M K2SO4

14. Phenol dimerises in benzene having van't Hoff factor 0.54. What is the degree of association?

(a)

0.46

(b)

92

(c)

46

(d)

0.92

15. Assertion: An ideal solution obeys Raoults Law
Reason: In an ideal solution, solvent-solvent, as well as solute-solute interactions, are similar to solute-solvent interactions.

(a)

both assertion and reason are true and reason is the correct explanation of assertion

(b)

both assertion and reason are true but reason is not the correct explanation of assertion

(c)

assertion is true but reason is false

(d)

both assertion and reason are false

16. In the molecule O= C = OB, the formal charge on OA, C and OB are respectively.

(a)

-1, 0, +1

(b)

+1, 0, -1

(c)

-2, 0, +2

(d)

0, 0, 0

17. Assertion: Oxygen molecule is paramagnetic.
Reason: It has two unpaired electron in its bonding molecular orbital.

(a)

both assertion and reason are true and reason is the correct explanation of assertion

(b)

both assertion and reason are true but reason is not the correct explanation of assertion

(c)

assertion is true but reason is false

(d)

Both assertion and reason are false

18. In ClF3, NF3 and BF3 molecules the chlorine, nitrogen and boron atoms are

(a)

sp3 hybridised

(b)

sp3 ,sp3 and sp2 respectively

(c)

sp2 hybridised

(d)

sp3d, sp3 and sp hybridised respectively

19. Which of these represents the correct order of their increasing bond order

(a)

\(C_2

(b)

\(C_2^{2-}

(c)

\(O_2^{2-}

(d)

\(O_2^{2-}

20. Hybridisation of central atom in PClinvolves the mixing of orbitals

(a)

s, px, py, dx2 , dx2-y2

(b)

s, px . py, pxy . dx2-y2

(c)

s, px, py, pz, dx2-y2

(d)

s, px, py, dxy, dx2-y2

21. Shape and hybridisation of IF5 are

(a)

Trigonal bipyramidal, Sp3d2

(b)

Trigonal bipyramidal, Sp3d

(c)

Square pyramidal, Sp3d2

(d)

Octahedral, Sp3d2

22. Pick out the incorrect statement from the following

(a)

Sp3 hybrid orbitals are equivalent and are at an angle of 109o 28' with each other

(b)

dsp2 hybrid orbitals are equivalent and bond angle between any two of them is 90o

(c)

All five sp3d hybrid orbitals are not equivalent out of these five sp3d hybrid orbitals, three are at an angle of 120o, remainir two are perpendicular to the plane containing the other three

(d)

none of these

23. In which of the following molecules /ions BF3, NO2-, H2O the central atom is sp2 hybridised?

(a)

NH2- and H2O

(b)

NO2- and H2O

(c)

BF3 and NO2-

(d)

BF3 and NH2-

24. Some of the following properties of two species, NO3- and H3O+ are described below. which one of them is correct?

(a)

dissimilar in hybridisation for the central atom with different structure

(b)

isostructural with same hybridisation for the Central atom

(c)

different hybridiration for the central atom with same structure

(d)

none of these

25. Xe F2 is isostructural with

(a)

SbCl2

(b)

BaCl2

(c)

TeF2

(d)

ICI2-

26. Shape of ClF3 is

(a)

Planar triangular

(b)

Pyramidal

(c)

'T' Shaped

(d)

none of these

27. Which of the following conditions is not correct for resonating structures?

(a)

the contributing structure must have the same number of unpaired electrons

(b)

the contributing structures should have similar energies

(c)

the resonance hybrid should have higher energy than any of the contributing structure

(d)

none of these

28. Among the following, the compound that contains, ionic, covalent and Coordinate linkage is

(a)

NH4Cl

(b)

NH3

(c)

NaCl

(d)

none of these

29. CaO and NaCl have the same crystal structure and approximately the same radii. It U is the lattice energy of NaCl, the approximate lattice energy of CaO is

(a)

U

(b)

2U

(c)

U/2

(d)

4U

30. The percentage of s-character of the hybrid orbitals in methane, ethane, ethene and ethyne are respectively

(a)

25, 25, 33, 3, 50

(b)

50, 50, 33, 3, 25

(c)

50, 25, 33, 3, 50

(d)

50, 25, 25, 50