Chemistry MCQs Test P 17

HN PHYSICS

Dipole Moment

1. Molecules with odd electron bond are

  1. paramagnetic
  2. unstable
  3. forms dimers at low temperature
  4. all are correct

Answer: (d)



2. In a crystal, atoms are located at the positions of

  1. maximum potential energy
  2. minimum potential energy
  3. zero potential energy
  4. indefinite potential energy

Answer: (b)

3. If the water molecule is linear

  1. it would have a very high boiling point
  2. it would be highly reactive
  3. its dipole moment would be zero
  4. it would be highly ionic

Answer: (c)

4. The percentage of ionic character of the bond between two atoms is calculated from the difference between their

  1. ionic radii
  2. electronegativities
  3. electron affinities
  4. ionisation energies

Answer: (b)

5. Which of the following is not correct for dipole moment?

  1. lone pair of electrons present on the central atom can give rise to the dipole moment
  2. the dipole moment is a vector quantity
  3. CO2 molecule has no dipole moment since C-O bonds are nonpolar
  4. the difference in electronegativities of combining atoms can lead to the dipole moment

Answer: (c)

6. For two ionic solids CaO and KI, identify the wrong statement among the following

  1. the lattice energy of CaO is much larger than KI
  2. KI is soluble in benzene
  3. CaO has a higher melting point
  4. KI has a lower melting point

Answer: (b)

7. A diatomic molecule has a dipole moment of 1.2D. If its bond distance is 1.0Ao, what fraction of electric charge “e” exists on each atom?

  1. 12% of e
  2. 18% of e
  3. 25% of e
  4. 30% of e

Answer: (c)

8. Find the species with a maximum dipole among the following

  1. NF3
  2. CO2
  3. NH3
  4. CH4

Answer: (c)

9. In conductors, opposite charges are separated by

  1. dielectric
  2. insulator
  3. microscopic distances
  4. large distances

Answer: (b)

10. Electric susceptibility is inversely proportional to

  1. permittivity
  2. polarization vector
  3. magnetic field intensity
  4. permeability

Answer: (a)

Overlapping and Bonds

1. Which of the following at ordinary temperature and pressure exists as a linear polymer due to extensive hydrogen bonding?

  1. H2O
  2. HCl
  3. HF
  4. NH3

Answer: (c)

2. The shape of SF3Cl3 molecule is

  1. triangle bi-pyramidal
  2. cubic
  3. octahedral
  4. tetrahedral

Answer: (c)

3. The structure of CH2=C=H2 is

  1. linear
  2. planar
  3. non-planar
  4. has several reasoning structure

Answer: (a)

4. Which is the correct arrangement of the molecules based on dipole moments?

  1. BF3 > NF3 > NH3
  2. NF3 > BF3 > NH3
  3. NH3 > BH3 > NF3
  4. NH3 > NF3 > BF3

Answer: (d)

5. When two ice cubes are pressed over each other, they unite to form one cube. Which of the following forces is responsible to hold them together?

  1. Ionic interaction
  2. covalent attraction
  3. van der waals forces
  4. hydrogen bond formation

Answer: (d)

6. Which of the following is diamagnetic?

  1. Superoxide ion
  2. carbon molecule
  3. unipositive ion of nitrogen molecule
  4. oxygen molecule

Answer: (b)

7. A molecule of fluorine is formed by

  1. the axial p-p orbital overlap
  2. the sidewise p-p orbital overlap
  3. the axial s-s orbital overlap
  4. the axial s-p orbital overlap

Answer: (d)

8. Which one of the following molecules has the smallest bonds?

  1. NH3
  2. PH3
  3. H2O
  4. H2Se

Answer: (d)

9. Polarity in a molecule and hence the dipole moment depends primarily on electronegativity to the constituent atoms and shape of a molecule. Which of the following has the highest dipole moment?

  1. CO2
  2. HI
  3. H2O
  4. SO2

Answer: (c)

10. The electron configuration of the outermost shell of the most electronegative element is

  1. 2s22p2
  2. 3s23p5
  3. 4s24p5
  4. 5s25p5

Answer: (a)

Freezing Point of The Solvent

1. Which one of the following gases has the lowest value of Henry’s law constant?

  1. N2
  2. He
  3. H2
  4. CO2

Answer: (d)

2. If 10ml of 0.1M aqueous solution of NaCl is divided into 1000 drops of equal volume. What will be the concentration of one drop?

  1. 0.01M
  2. 0.10M
  3. 0.001M
  4. 0.0001M

Answer: (b)

3. A 0.5 molal solution of ethylene glycol in water is used as a coolant in a car. If the freezing point constant of water be 1.86oC per mole, the mixture shall freeze at

  1. 0.93oC
  2. -0.93oC
  3. 1.86oC
  4. -1.86oC

Answer: (b)

4. Which statement is true for a solution of 0.020M H2SO3?

  1. 2 litre of the solution contains 0.020 mole of SO42-
  2. 2 litre of the solution contains 0.080 mole of H3O+
  3. 1 litre of the solution contains 0.020 mole of H3O+
  4. None of these

Answer: (b)

5. A 500g toothpaste sample has 0.2g fluoride concentration. What is the concentration of F in terms of ppm level?

  1. 250
  2. 300
  3. 400
  4. 1000

Answer: (c)

6. If at a certain temperature the vapour pressure of pure water is 25 mm Hg and that of a very dilute aqueous urea solution is 24.5mm Hg, the molality of the solution is

  1. 0.02
  2. 1.2
  3. 1.11
  4. 0.08

Answer: (c)

7. Which of the following 0.10m aqueous solutions will have the lowest freezing point?

  1. Al2(SO4)3
  2. C6H12O6
  3. KCl
  4. C12H22O11

Answer: (a)

8. The amount of urea to be dissolved in 500 cc of water (K = 1.86oC mol-1) to produce a depression of 0.186oC in the freezing point is

  1. 9g
  2. 6g
  3. 3g
  4. 0.3g

Answer: (c)

9. The empirical formula of a nonelectrolyte is CH2O. A solution containing 6g of the compound exerts the same osmotic pressure as that of 0.05M glucose solution at the same temperature, The molecular formula of the compound is

  1. C2H4O2
  2. C3H6O3
  3. C5H10O5
  4. C4H8O4

Answer: (d)

10. The molar mass of the solute sodium hydroxide obtained from the measurement of the osmotic pressure of its aqueous solution at 27oC is 25gmol-1. Therefore its ionization solution at 27oC is 25 g mol-1. Therefore its ionization percentage in this solution is

  1. 75
  2. 60
  3. 80
  4. 70

Answer: (b)

Cell Constant and Electrochemical Cells

1. Oxygen has a +2 oxidation state in

  1. H2O
  2. H2O2
  3. F2O
  4. SO2

Answer: (c)

2. Which of the following is the strongest reducing agent?

  1. Li
  2. Na
  3. Mg
  4. Ca

Answer: (a)

3. When the salt bridge is removed from a cell, its voltage

  1. will increase
  2. will decrease to half
  3. will decrease to zero
  4. will not change

Answer: (c)

4. When a dilute solution of H2SO4 is electrolysed using a platinum electrode, at anode the gas evolved is

  1. SO3
  2. SO2
  3. H2
  4. O2

Answer: (d)

5. The oxidation number of sulphur in Caro’s acid is

  1. +4
  2. +5
  3. +6
  4. +8

Answer: (c)

6. Which of the following is the most powerful reducing agent?

  1. H2S
  2. H2SO3
  3. SnCl2
  4. HNO2

Answer: (a)

7. Which of the following substances can act as both oxidising and reducing agent?

  1. KMnO4
  2. K2Cr2O7
  3. HNO3
  4. H2O2

Answer: (d)

8. Electrolytes conduct electric current

  1. by the movement of ions
  2. by the movement of atoms
  3. by the movement of molecules
  4. by the movement of electrons from the cathode to anode

Answer: (d)

9. The reductant may be defined as a substance, whose oxidation no of the atom

  1. increases
  2. decreases
  3. remains constant
  4. may increases or decreases

Answer: (a)

10. Which of the following is not an example of an oxidizing agent?

  1. hydrogen peroxide
  2. potassium dichromate
  3. nitric acid
  4. hydrogen sulphide

Answer: (d)

11. The conductance in electrolyte conductors is due to

  1. Either movement of electrons or ions
  2. The flow of free mobile electrons
  3. Movement of ions
  4. None of the above

Answer: (c)

12. The cell constant of a conductivity cell

  1. Changes with a change of concentration of electrolyte
  2. Remains constant for a cell
  3. changes with a change of electrolyte
  4. changes with change in temperature

Answer: (b)

Compounds of Transitional Elements

1. The 3d transition series contains elements having an atomic number from

  1. 21 to 30
  2. 21 to 31
  3. 22 to 30
  4. 21 to 29

Answer: (a)

2. The first transition element is

  1. copper
  2. nickel
  3. scandium
  4. vanadium

Answer: (c)

3. Transition metals are generally coloured because

  1. they absorb electromagnetic radiations
  2. their penultimate d-subshells are fully filled
  3. of d-d transition
  4. none of the above

Answer: (c)

4. Atomic radii of d-block elements in a series

  1. decreases with increase in atomic number
  2. increases with increase in atomic number
  3. remains constant
  4. none of the above

Answer: (a)

5. Formation of interstitial compounds makes the transition metals more

  1. soft
  2. ductile
  3. malleable
  4. none of the above

Answer: (d)

6. Paramagnetism is common in

  1. s-block elements
  2. p-block elements
  3. d-block elements
  4. any of them

Answer: (c)

7. Transition metals are complexes act as

  1. Lewis acid
  2. Lewis base
  3. Neutral
  4. none of the above

Answer: (a)

8. Transition elements exhibit variable valency because they release electrons from

  1. ns orbitals
  2. np orbitals
  3. (n-1)d orbitals
  4. (n-1)d & ns orbitals

Answer: (c)

9. The density of transition metals in a series

  1. decreases gradually
  2. increases gradually
  3. remains constant
  4. may increase or decrease

Answer: (b)

10. In industrial processes, transition elements and their oxides are used as

  1. surfactants
  2. insecticides
  3. catalyst
  4. any of them

Answer: (c)

Water or Hydride of Oxygen

1. Water is oxidised to oxygen by

  1. H2O2
  2. KMnO4
  3. ClO2
  4. fluorine

Answer: (d)

2. The H-O-H bond angle in a water molecule is about

  1. 90o
  2. 105o
  3. 135o
  4. 180o

Answer: (b)

3. The action of water or dilute mineral acids on metals can give

  1. tritium
  2. dihydrogen
  3. trihydrogen
  4. mono hydrogen

Answer: (b)

4. Reaction of potassium with water is

  1. hydrolysis
  2. absorption
  3. exothermic
  4. Endothermic

Answer: (c)

5. Water softening by Clarke’s process uses

  1. potash alum
  2. calcium bicarbonate
  3. calcium hydroxide
  4. sodium bicarbonate

Answer: (c)

6. A variety of water which contains soluble salts of Ca and Mg is known as

  1. soft water
  2. heavy water
  3. conductivity water
  4. hard water

Answer: (d)

7. Oxygen does not react with

  1. Na
  2. P
  3. Cl
  4. S

Answer: (c)

8. The gas O3 (ozone) cannot oxidise

  1. KI
  2. FeSo4
  3. KMnO4
  4. K2MnO4

Answer: (c)

9. The molarity of pure water at 277K is

  1. 1M
  2. 5M
  3. 55.5M
  4. 2.5M

Answer: (c)

10. Which one of the following substances has the highest proton affinity?

  1. NH3
  2. H2O
  3. PH3
  4. H2S

Answer: (a)

Reversible and Irreversible Reaction

1. The net energy change in a reversible cyclic process is

  1. 3/2 RT
  2. zero
  3. always > 0
  4. always < 0

Answer: (b)

2. Which of the following is an extensive property?

  1. temperature
  2. pressure
  3. mass/volume ratio
  4. energy

Answer: (d)

3. Which of the following represents the largest amount of energy?

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

Answer: (c)

4. Which of the following is correct for an adiabatic process?

  1. 𐤃E = q
  2. q = 0
  3. q = +w
  4. P𐤃 V = 0

Answer: (b)

5. The mixing of gases is generally accompanied by

  1. decrease in entropy
  2. a decrease in free energy
  3. change in heat content
  4. increase in free energy

Answer: (b)

6. One litre atmosphere is approximately equal o

  1. 101J
  2. 8.314J
  3. 931J
  4. 19.2J

Answer: (a)

7. The enthalpy change for a given reaction at 298K is -x J/mol. If the reaction occurs spontaneously at 298K the entropy change at that temperature

  1. can be negative but larger than x/298
  2. can be negative but smaller than x/298
  3. cannot be negative
  4. cannot be positive

Answer: (b)

8. The initial energy change (𐤃U) of a process does not depend upon

  1. amount of substance undergoing the change
  2. temperature
  3. path of the process
  4. nature of substance undergoing the change

Answer: (c)

9. Vibrational energy is

  1. partial potential and partly kinetic
  2. only potential
  3. only kinetic
  4. neither kinetic nor potential

Answer: (a)

10. The total entropy change for a system and its surroundings increases if a process is

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

Answer: (d)

Law of Mass Action

1. Which of the following is not correct?

  1. the rate law is an experimental fact, but the law of mass action is theoretical
  2. the rate law is always different from the expression of the law of mass action
  3. the rate law is more informative than the law of mass action for the development of a mechanism
  4. the order of a reaction is equal to the sum of the powers of the concentration terms in the rate law.

Answer: (b)

2. The temperature coefficient of a reaction is 2. How many times the rate of reaction increases when the temperature is increased from 30oC to 60oC.

  1. 4 times
  2. 6 times
  3. 8 times
  4. 16 times

Answer: (c)

3. If a reaction with t1/2 = 69.3 sec, has a rate constant 10-2 per sec the order is

  1. zero
  2. 1
  3. 2
  4. 3

Answer: (b)

4. K for a zero-order reaction is 2 x 10-2 mole/L/sec. If the concentration of reactant after 25 sec is 0.5M, the initial concentration must have been

  1. 0.5M
  2. 1.25M
  3. 12.5M
  4. 1.0M

Answer: (d)

5. A first-order reaction is 75% complete after 32 minutes. When was 50% of the reaction completed?

  1. 16min
  2. 8min
  3. 4min
  4. 32min

Answer: (a)

6. What is the half-life of a radioactive substance if 87.5% of any given amount of the substance disintegrate in 40 minutes?

  1. 160 min
  2. 10 min
  3. 20 min
  4. 13 min 20 sec

Answer: (d)

7. Half-life of 10g of radioactive substance is 10 days. The half-life of 20 g is

  1. 10 days
  2. 5 days
  3. 20 days
  4. 40 days

Answer: (a)

8. The chemical reactions in which reactants need a high amount of activation energy are generally

  1. fast
  2. slow
  3. very fast
  4. instantaneous

Answer: (b)

9. For a reaction A → Products the rate of reaction doubles when the concentration of A is increased by 4 times. The order of the reaction is

  1. 4
  2. 0
  3. 1/2
  4. 1

Answer: (c)

10. The number of atoms or molecules whose concentration alters during a chemical change is its

  1. molecularity
  2. order of reaction
  3. change in reaction
  4. none

Answer: (b)




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