The percentage of an element M is 53 in its oxide of molecular fo

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 Multiple Choice QuestionsMultiple Choice Questions

81.

At 25°C, at 5% aqueous solution of glucose (molecular weight = 180g mol-1) is isotonic with a 2% aqueous solution containing and unknown solute. What is the molecular weight of the unknown solute?

  • 60

  • 80

  • 72

  • 63


82.

200 mL of water is added to a 500 mL of 0.2 M solution. What is the molarity of this diluted solution?

  • 0.5010M

  • 0.2897M

  • 0.7093

  • 0.1428


83.

Which of the following pairs of substances would give same gaseous product on reaction with water?

  • Na and Na2O2

  • Ca and CaH2

  • Ca and CaO

  • Ba and BaO2


84.

When 200 mL of aqueous solution of HCl (pH = 2) is mixed with 300 mL of an aqueous solution of NaOH (pH = 12) the pH of the resulting mixture is

  • 10

  • 2.7

  • 4.0

  • 11.3


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85.

In acid medium, Zn reduces nitrate ion to NH4+ ion according to the reaction,

Zn + NO3-→ Zn2+ + NH4+ + H2O (unbalanced).

How many moles of HCl are required to reduce half a mole of NaNO3 completely ? Assume the availability of sufficient Zn.

  • 5

  • 4

  • 3

  • 2


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86.

The percentage of an element M is 53 in its oxide of molecular formula M2O3. Its atomic mass is about

  • 45

  • 9

  • 27

  • 36


C.

27

Percentage of element M in M2O3 = 53
Let the atomic mass of M = x
Mass of M in M2O3 = 2x
Total atomic mass of M2O3 = 2x + 16 x 3
                                        = 2x + 48
Percentage of an element

=Mass of an element in a compound Total mass of compound × 10053 = 2x2x + 48× 10053(2x + 48) = 200x                    x = 27 


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87.

The relative lowering of vapour pressure of a dilute aqueous solution containing non-volatile solute is 0.0125. The molality of the solution is about

  • 0.70

  • 0.50

  • 0.90

  • 0.80


88.

The pH of a solution obtained by mixing 50 mL of 1 N HCl and 30 mL of 1 N NaOH is [log 2.5 = 0.3979]

  • 12.042

  • 0.6021

  • 0.3979

  • 3.979


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89.

0.1 mole of a carbohydrate with empirical formula CH2O contains 1 g of hydrogen. What is its molecular formula?

  • C2H4O2

  • C5H10O5

  • C3H6O3

  • C6H12O6


90.

How much of sulphur is present in an organic compound, if 0.53 g of the compound gave 1.158 g of BaSO4 on analysis ? 

  • 10%

  • 20%

  • 30%

  • 15%


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