MOLE CONCEPT PART G

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MOLE CONCEPT PART G


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MOLE-II : Basic Stoichiometry

Section (D) : Stoichiometry, Equation based calculations (Elementary level single equation or 2)

D-1 12 g of alkaline earth metal gives 14.8 g of its nitride. Atomic weight of metal is –

(A) 12                            (B) 20                         (C) 40                         (D) 14.8

D-2       For the reaction 2P + Q R, 8 mol of P and excess of Q will produce :

(A) 8 mol of R                (B) 5 mot of R             (0) 4 mol of R             (D) 13 mol of R

D-3 If 1.5 moles of oxygen combine with Al to form Al203, the weight of Al used in the reaction is :

(A) 27 g                         (B) 40.5 g                   (C) 54g                       (D) 81 g

D-4 How many liters of CO2 at STP will be formed when 0.01 mol of H2SO4 reacts with excess of Na2CO3 .

Na2CO3 + H2SO4 _____________ > Na2SO4 + CO2 + H2O

(A) 22.4 L                      (B) 2.24 L                    (C) 0.224 L                  (D) 1.12 L

D-5. When 100g of ethylene polymerises entirely to polyethene, the weight of polyethene formed as per the equation

n(C2H4)            (-0H2-CH2-), is :

(A) (n/2)g                       (B) 100g                     (C) (100/n)g                (D) 10Ong

D-6. How many moles of potassium chlorate need to be heated to produce 11.2 litre oxygen at N.T.P.

(A) –2

1                                 1 -3                                                                                                                                      1 –4                                                                                                                                      2

mol                    (B)              mol                    (C)              mol                   (D) 3 rnol

Section (E) : Limiting reagent, % Excess, % Yield / Efficiency

  • Calculate the amount of Ni needed in the Mond’s process given below

NH- 4C0 ___ > Ni(C0)4

If CO used in this process is obtained through a process, in which 6 g of carbon is mixed with 44 g CO2. (A) 14.675 g            (B) 29 g                                (C) 58 g                                 (D) 28 g

  • For the reaction 2P + Q —-> R, 8 mol of P and 5 mol of Q will produce

(A) 8 mol of R              (B) 5 mol of R             (C) 4 mol of R               (D) 13 mol of R

  • How many mole of Zn(FeS2) can be made from 2 mole zinc, 3 mole iron and 5 mole sulphur.

(A) 2 mole                             (B) 3 mole                            (C) 4 mole                   (D) 5 mole

  • Equal weight of ‘X’ (At. wt. = 36) and ‘Y’ (At. wt. = 24) are reacted to form the compound X2Y3. Then :

(A) X is the limiting reagent                                        (B) Y is the limiting reagent

(C) No reactant is left over and mass of X2Y3 formed is double the mass of ‘X’ taken

(ID) none of these

  • 5 mole of H2SO4 is mixed with 0.2 mole of Ca (OH)2. The maximum number of moles of CaSO4 formed is

(A) 0.2                                    (B) 0.5                                   (C) 0.4                        (D) 1.5

  • The mass of 70% H2SO4 required for neutralisation of 1 mol of NaOH.

(A) 49 gm                              (B) 98 gm                            (C) 70 gm                         (D) 34.3 gm

  • In a certain operation 358 g of TiCI4 is reacted with 96 g of Mg. Calculate % yield of Ti if 32 g of Ti is actually
    358

obtained [At. wt. Ti = 48, Mg = 24] [Hint :            = 1.88]

(A) 35.38 %                          (B) 66.6 %                           (C) 100%                    (0) 60 %

Section (F) : Principle of atom conservation (POAC), Reactions in sequence & parallel, Mixture analysis, `)/0 Purity

F-1.                 25.4 g of iodine and 14.2g of chlorine are made to react completely to yield a mixture of ICI and ICI,. Calculate

the number of moles of ICI and 1013 formed.

(A) 0.1 mole, 0.1 mole                                                (B) 0.1 mole. 0.2 mole

(C) 0.5 mole, 0.5 mole                                                (D) 0.2 mole, 0.2 mole

What weights of P406 and will be produced by the combustion of 31g of P4 in 32g of oxygen leaving no

P4 and 02.

(A) 2.75g, 219.5g                 (B) 27.5g. 35.5g                  (C) 55g, 71g            (D) 17.5g, 190.5g

-3. 0.05 mole of LiAIH, in ether solution was placed in a flask containing 74g (1 mole) of t-butyl alcohol. The product LiAIHCl2H2703 weighed 12.7 g. If Li atoms are conserved, the percentage yield is : (Li = 7, Al = 27, H = 1,0= 12,0= 16).

(A) 25%                                 (B) 75%                                (C) 100%                  (D) 15%

F-6.* A sample of a mixture of CaCl2 and NaCI weighing 4.44 gm was treated to precipitate all the Ca as CaCO3, which was then heated and quantitatively converted to 1.12g of CaO. (At . wt. Ca = 40, Na = 23, CI = 35.5)

(A) Mixture contains 50% NaCI                                   (B) Mixture contains 60% CaCl2

(C) Mass of CaCl2 is 2.22 g                                              (D) Mass of CaCl2 1.11 g

MOLE-Ill : Oxidation Reduction & Balancing Redox Equations

 

Section (G) : Basics of oxidation number

  • The oxidation number of Oxygen in Na202 is :

(A) + 1                                  (B) + 2                                  (C) — 2

  • In FeCr2O4, the oxidation numbers of Fe and Cr are :

(A) + 2 and + 3                   (B) 0 and + 2                   (C) + 2 and + 6

  • The oxidation number of Phosphorus in Mg2P2O7 is :

(A) + 3                                  (B) + 2                                (C) + 5

 

G-4.                          The oxidation states of Sulphur in the anions S032- , S2042- and S2062- follow the order :

(A) S2062 < S2042 < S032                                                          (B) S2042 < SO32 < S2062

(C) S032- < S2042 < S2062                                                (0) 52042 < S2062 < S032-

G-5. Match List-I (Compounds) with List-II (Oxidation states of Nitrogen) and select answer using the codes given

below the lists :

List-I                                                      List-II

  • NaN3 (1)                                 +5
  • N2H2 (2)                                 +2
  • NO (3)                                —1/3
  • N205 (4)                             —1

(Code) :

(a)        (b)          (c)       (d)                              (a)        (b)       (c)       (d)

(A)          3          4          2          1                     (B)                 4          3          2         1

(C)       3          4          1          2                     (D)                 4          3          1         2

G-6.            1 mole of N2H4 loses ten moles of electrons to form a new compound Y. Assuming that all the nitrogen appears

in the new compound, what is the oxidation state of nitrogen in Y? (There is no change in the oxidation state of hydrogen).

(A) — 1                                                      (B) — 3                                 (C) + 3                                 (D) ÷ 5

G-7. The average oxidation state of Fe in Fe304 is :

(A) 2 and 3                           (B) 8/3                                  (C) 2                                     (D) 3

G-8.* Which of the following are examples of disproportionation reaction :

(A) HgO __ > Hg + 02                                                  (B) KC1O3 _______ > KCI + 02

(C) KCIO3___________ > KCIO4 + KCI                                     (ID) 012 + OH– ___________________ > CIO + CL + H2O

Section (H) : Balancing redox reactions

H-1.        In the reaction xHI + yHNO3                           NO + 12 + H2O, upon balancing with whole number coefficients :

 

(A)x=3,y=2                   (B)x=2,y=3

(C) x = 6, y = 2                     (D) x = 6, y= 1

 

  • For the redox reaction Mn04 + C2042- + H+ __________ > Mn2+ + CO2 + H2O,

the correct whole number stoichiometric coefficients of Mn04, C2042- and H+ are respectively: (A) 2, 5, 16                                         (B) 16, 5, 2                           (C) 5, 16, 2                            (D) 2, 16, 5

  • For the redox reaction xP4 + yHNO3 H3PO4 + NO2 + H2O, upon balancing with whole number coefficients:

 

(A)x=1,y=5                  (B) x = 2, y = 10

(C) x = 1, y = 20                  (D) x = 1, y = 15

  • In the reaction X + X03 + H– _ > X2 + H20, the molar ratio in which X and X03 react is :

(A) 1 : 5                                 (B) 5 : 1                                (C) 2 : 3                                (D) 3 : 2

  • CN is oxidised by NO3 in presence of acid :

a CN + b NO3 + c I-I+ ______________________________ > (a + b) NO + a CO2 + H2O

What are the whole number values of a, b, c in that order :

(A) 3, 7, 7                               (B) 3, 10, 7                             (C) 3, 10, 10

H-6.* In the following reaction : Cr(OH)3 + OH +103 -* Cr042- + H2O +

(A)I03 is oxidising agent                               (B) Cr(OH)3 is oxidised

(C) 6e are being taken per iodine atom                     (0) None of these

(0) 3, 7, 10

 

MOLE-IV : Concentration Measurement

Section (1) : Units of concentration measurement, Interconversion of concentration units

I-I. 500 mL of a glucose solution contains 6.02 x 1022 molecules. The concentration of the solution is

(A) 0.1 M                                (B) 1.0 M                               (C) 0.2 M                     (ID) 2.0 M

1-2.     Equal moles of H2O and NaCI are present in a solution. Hence, molality of NaCl solution is :

(A) 0.55                       (B) 55.5                      (C) 1.00                     (D) 0.18

1-3. Decreasing order of mass of pure NaOH in each of the aqueous solution.

(1) 50 g of 40% (WIW) NaOH

  • 50 ml of 50% (W/V) NaOH (d„ = 1.2 g/ml).
  • 50 g of 15 M NaOH = 1 g/m1).

(A) I, 11, III                           (B)         11.1                                       (0)11, III, I                      (D)III=l1=I.

1-4.                                                                Mole fraction of A in H2O is 0.2. The molality of A in H2O is :

(A) 13.9                       (B) 15.5                      (C) 14.5                              (D) 16.8

1-5. What is the molarity of H2SO4 solution that has a density of 1.84 g/cc and contains 98% by mass of H2SO4?

(Given atomic mass of S = 32)

(A) 4.18 M                             (B) 8.14 M                            (C) 18.4 M                   (ID) 18 M

1-6. The molarity of the solution containing 2.8%( mass / volume) solution of KOH is : (Given atomic mass of

K= 39 ) is :

(A) 0.1 M                                (B) 0.5 M                               (C) 0.2 M                    (D) 1 M

M
1-7.          A solution of FeCl3 is To  its molarity for Cl ion will be :

m

(A)                               (B) To-                                   (C) 10                          (0)

Section (J) : Dilution & Mixing of two liquids

  • If 500 ml of 1 M solution of glucose is mixed with 500 me of 1 M solution of glucose final molarity of solution will be

(A) 1 M                                   (B) 0.5 M                               (C) 2 M                         (D) 1.5 M

  • The volume of water that must be added to a mixture of 250 ml of 0.6 M HCI and 750 ml of 2 M HCI to obtain 0.25 M solution of HCI is :

(A) 750 mi                             (B) 100 ml                            (C) 200 mt               (D) 300 m

  • What volume of a 0.8 M solution contains 100 milli moles of the solute?

(A) 100 mL                  (B) 125 mL                 (C) 500 mL                 (ID) 62.5 mL

  • The molarity of CI in an aqueous solution which was (w/V) 2% NaCI, 4% CaCl2 and 6% NH CI will be

(A) 0.342                               (B) 0.721                              (C) 1.12                               (ID) 2.18

J-5.    2M of 100 ml Nat SO4is mixed with 3M of 100 ml NaCI solution and 1M of 200 ml CaCl2 solution. Then the

ratio of the concentration of cation and anion.

(A) 1/2                          (B) 2                            (C) 1,5                       (ED) 1


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