Important Questions for NEET Chemistry

Free Books, Notes, PYQs, Mind Maps
22
  1. Electrolysis of brine produces

A. chlorine gas
B. hydrogen gas
C. sodium hydroxide
D. all the above

Answer: (d)

  1. A reactant containing the element that is oxidised is called

A. reducing agent
B. oxidising agent
C. hydrogen
D. sublime

Answer: (a)

  1. By losing one or two electrons the atoms of metal are

A. oxidised
B. reduced
C. hydrogenated
D. sublimated

Answer: (a)

  1. Electrolytes conduct electricity in

A. solid state
B. liquid state
C. gaseous state
D. plasma state

Answer: (b)

  1. Loss of hydrogen atoms by an element is called

A. hydrogenation
B. oxidation
C. reduction
D. sublimation

Answer: (b)

23
  1. The electrolyte among the following is

A. NaOH
B. Urea
C. glucose
D. benzene

Answer: (a)

  1. O-O-H bond angle in H2O2 is

A. 97°
B. 106°
C. 120°
D. 109°28′

Answer: (a)

  1. Which of the following is very high for proton?

A. radius
B. ionization potential
C. charge
D. hydration energy

Answer: (d)

  1. The list which contains only elements is

A. air, water, oxygen
B. hydrogen, oxygen, brass
C. air, water, fire, earth
D. calcium, sulphur, carbon

Answer: (d)

  1. The smallest part of an element that cannot exist as a free state is

A. ion
B. charge
C. atom
D. molecule

Answer: (c)

24
  1. Which of the following methods is not used for the prevention of corrosion?

A. greasing
B. painting
C. plating
D. Heating
Answer: (d)

  1. Widening of a river valley takes place due to

A. corrosion
B. lateral erosion
C. corrasion
D. hydraulic action
Answer: (b)

  1. Elements which have properties of metals and nonmetals are

A. amorphous
B. crystalline
C. metalloids
D. metals
Answer: (c)

  1. Corrosion can be prevented by

A. alloying
B. tinning
C. galvanizing
D. all of the above
Answer: (d)

  1. Galvanic cells are also named as

A. electrolytic cells
B. battery cells
C. daniel cells
D. john cells
Answer: (a)

25
  1. Voltaic cells generate electricity by

A. spontaneous redox reaction
B. non spontaneous redox reaction
C. sublimation reaction
D. thermochemical reaction
Answer: (a)

  1. Galvanization is a method to

A. protect the iron metal from corrosion
B. extract iron from its ore
C. protect food from rancidity
D. improve the ductility property of the metal
Answer: (a)

  1. Rusting of iron could take place in

A. distilled water
B. ordinary water
C. distilled and ordinary water
D. none of the above
Answer: (c)

  1. Which of the following non-metals is liquid at the room temperature?

A. iodine
B. bromine
C. carbon
D. sulphur
Answer: (b)

  1. During roasting which of the following poisonous gas is mainly produced

A. CO
B. CO2
C. SO2
D. N2O
Answer: (c)

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26
  1. The concentration of dissolved oxygen in cold water can go up to

A. 14 ppm
B. 8 ppm
C. 10 ppm
D. 16 ppm
Answer: (c)

  1. The quantity of DDT at each trophic level in the food chain

A. decreases
B. remains the same
C. increases
D. changes
Answer: (c)

  1. Formation of London smog takes place in

A. winter during day time
B. summer during day time
C. summer during morning time
D. winter during morning time
Answer: (d)

  1. Brewery and sugar factory waste alter the quality of a water body by increasing

A. temperature
B. turbidity
C. pH
D. COD and BOD
Answer: (d)

5.In a coal-fired power plant electrostatic precipitators are installed to control the emission of

A. SO2
B. NO2
C. SPM
D. CO
Answer: (c)

27
  1. Which of the following serves as an indicator of atmospheric pollution?

A. fern
B. liverworts
C hornworts
D. epiphytic lichens
Answer: (d)

  1. In 1984, the Bhopal gas tragedy took place because methyl isocyanate

A. reacted with ammonia
B. reacted with water
C. reacted with DDT
D. reacted with CO2
Answer: (b)

  1. Negative soil pollution is

A. reduction in soil productivity due to erosion and overuse
B. reduction in soil productivity due to addition of pesticides and industrial wastes
C. converting fertile land into harden land by dumping ash, sludge and garbage
D. None of the above
Answer: (a)

  1. Air pollution that occurs in sunlight is

A. reducing smog
B. acid rain
C. oxidizing smog
D. fog
Answer: (c)

  1. The layer of atmosphere between 10km to 50km above the sea level is called as

A. troposphere
B. thermosphere
C. stratosphere
D. mesosphere
Answer: (c)

28
  1. BCl3 is a planar molecule whereas NCl3 is pyramidal because

A. B-Cl bond is more polar than NaCl bond
B. N-Cl bond is more covalent than B-Cl bond
C. the nitrogen atom is smaller than boron atom
D. BCl3 has no pair but NCl3 has a lone pair of electrons
Answer: (d)

  1. In which solvent NaCl has maximum solubility?

A. H2O
B. C2H5OH
C. CH3COCH3
D. C2H5OC2H5
Answer: (a)

  1. Which one of the following pairs of molecules will have permanent dipole moments for both members?

A. NO2 and CO2
B. NO2 and O3
C. SiF4 and CO2
D. SiF4 and NO2
Answer: (b)

  1. Which of the following compounds has the smallest bond angle in its molecule?

A. H2O
B. H2S
C. NH3
D. SO2
Answer: (b)

  1. Which one of the following properties is not shown by NO?

A. it is diamagnetic in the gaseous state
B. it is a neutral oxide
C. it combines with oxygen to form nitrogen dioxide
D. its bond order is 2.5
Answer: (a)

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29
  1. The compound which contains both ionic and covalent bond:

A. KCl
B. KCN
C. CH4
D. H2
Answer: (b)

  1. The maximum number of 90o angles between bond pair-bond pair of electrons is observed in

A. dsp2 hybridisation
B. sp3d hybridisation
C. dsp3 hybridisation
D sp3d2 hybridisation
Answer: (d)

  1. Ether is more volatile than alcohol having the same molecular formula. This is due to

A. alcohols having resonance structures
B. intermolecular hydrogen bonding in ethers
C. intermolecular hydrogen bonding in alcohols
D. the dipolar character of ethers
Answer: (c)

  1. The main axis of a diatomic molecule is z, molecular orbital px and py overlap to form which of the following orbital?

A. pi molecular orbital
B. sigma molecular orbital
C. gamma molecular orbital
D. No bond will be formed
Answer: (a)

  1. Total number of lone pair of electrons in I3- ion is

A. 3
B. 6
C. 9
D. 12
Answer: (c)

30
  1. The hybridisation of phosphorous in POCl3 is the same as in

A. P in PCl3
B. S in SF4
C. Cl in ClF3
D. B in BCl3
Answer: (a)

  1. If the bond length and dipole moment of diatomic molecules are 1.25Ao and 1.0D respectively, what is the percent ionic character of the bond?

A. 10.66
B.12.35
C. 16.66
D. 19.33
Answer: (c)

  1. The molecule MLx is planar with six pairs of electrons around M in the valence shell. The value of x is

A. 6
B. 2
C. 4
D. 3
Answer: (c)

  1. Total number of electron pairs in PCl5, PCl4+ and PCl6– are respectively

A. 20, 16, 24
B. 24, 16, 20
C. 16, 20, 24
D. 24, 20, 16
Answer: (a)

  1. If the water molecule is linear

A. it would have a very high boiling point
B. it would be highly reactive
C. its dipole moment would be zero
D. it would be highly ionic
Answer: (c)

31
  1. The molecule, which contains sp3d2 and p orbitals overlapping in it is

A. PCl5
B. BrF5
C. ClF3
D. IF7

Answer: (b)

  1. Homolytic fission of C-C bond of ethane (C2H6) which gives an intermediate in which carbon atom is

A. sp3 hybridised
B. sp2 hybridised
C. sp hybridised
D. sp3d hybridised

Answer: (b)

  1. Which of the following compounds has the electron pair geometry as trigonal bipyramidal with three equatorial positions occupied by lone pairs of electrons?

A. AlCl3
B. XeF2
C. Pt(NH3)2Cl
D. CH3MgBr

Answer: (b)

  1. Select correct statement

A. Cations with 18 electron shells have greater polarising power than the cations with 8-electron shells.
B. Inner shell electrons have a poor shielding effect on the nucleus and thus electronegativity of the 18 electron shell is increased.
C. CuCl is covalent and NaCl is ionic
D. All are correct statements

Answer: (d)

  1. In BrF3 molecule the lone pairs occupy an equatorial position to minimise

A. lone pair-bond pair repulsion only
B. bond pair-bond pair repulsion only
C. lone pair-lone pair repulsion and lone pair-bond pair repulsion
D. lone pair-lone pair repulsion only

Answer: (d)

32
  1. When two species A and B form an electron-pair bond and A does not provide its electrons for bonding, the bond present between A and B must be

A. ionic
B. covalent
C. dative
D. Hydrogen
Answer: (c)

  1. Each of the following pairs of chemical species will combine. Which of the following combinations is best explained by the coordinate covalent bond?

A. H2 + I2
B. Mg +O2
C. Cl + Cl
D. H+ + H2O
Answer: (d)

  1. BF3 forms an adduct with NH3 because

A. nitrogen has a high electronegativity
B. boron has a high electronegativity
C. boron has an empty p-orbital and nitrogen has one lone pair of electrons
D boron has an electropositive character
Answer: (c)

  1. Protons play an important role in which type of bonding?

A. electrovalent
B. hydrogen
C. Covalent
D. coordinate
Answer: (d)

  1. Which of the following compounds contain all three types: ionic, covalent and dative bonds?

A CuSO4.5H2O
B. Solid N2O5
C. (NH4)2SO4
D. All
Answer: (d)

33
  1. The type of bond formed during the hydration of cation is

A. ionic
B. covalent
C. electrostatic
D. dative bond
Answer: (d)

  1. Which of the following compounds has electrovalent linkage?

A. CH3Cl
B. NaCl
C. CH4
D. Cl2
Answer: (b)

3.Which of the following bonds has the most polar character?

A. C-O
B. C-Br
C. C-S
D. C-F
Answer: (d)

  1. A molecule with multiple covalent bonds is

A. C2H4
B. H2
C. F2
D. N2
Answer: (d)

  1. The weakest bond is

A. Hydrogen
B. Van der Waals
C. Covalent
D. Coordinate
Answer: (b)

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34
  1. In which of the following C-C bond length is least?

A. benzene
B. diamond
C. ethylene
D. acetylene
Answer: (d)

  1. The paramagnetic nature of oxygen molecule is explained by

A. Valence bond theory
B. Heitler London theory
C. Hund Mulliken theory
D. none of the above
Answer: (c)

  1. The bonds present in CuSO4.5H2O are

A. electrovalent and coordinate
B. covalent and coordinate
C. electrovalent and covalent
D. electrovalent, covalent and coordinate
Answer: (d)

  1. An element having 4 electrons in its outermost orbit forms bond by

A. losing electrons
B. gaining electrons
C. sharing electrons
D. any of the above
Answer: (c)

  1. Elements with electronegativities 1.2 and 3.0 form

A. electrovalent bond
B. covalent bond
C. coordinate bond
D. metallic bond
Answer: (a)

35
  1. Electrovalent compounds are

A. low melting
B. insoluble in polar solvents
C. conductors in the fused state
D. none of the above
Answer: (c)

  1. Ionic compounds don’t conduct electricity in

A. solution
B. fused state
C. solid state
D. none of the above
Answer: (c)

  1. When an element of very low ionization potential reacts with an element of very high electron affinity

A. a covalent bond is formed
B. an electrovalent bond is formed
C. a metallic bond is formed
D. no bond is formed
Answer: (b)

  1. The bond between two atoms of the same element is

A. polar covalent bond
B. ionic bond
C. non-polar covalent bond
D. none of the above
Answer: (c)

  1. The percentage of ionic character of a bond is calculated by the difference in

A. size of atoms
B. ionization potential of atoms
C. electronegativity of atoms
D. atomic volumes of atoms
Answer: (c)

36
  1. Which of the following represents a redox reaction?

A. NaOH + HCl → NaCl + H2O
B. BaCl2 + H2SO4 → BaSO4 + 2HCl
C. CuSO4 + 2H2O → Cu(OH)2 + H2SO3
D. Zn + 2HCl → ZnCl2 + H2
Answer: (d)

  1. Which reaction involves neither oxidation nor reduction?

A. CrO42- -→ Cr2O72-
B. Cr → CrCl3
C. Na → Na+
D. 2S2O32- → S4O62-
Answer: (a)

  1. Zn gives H2 gas with H2SO4 and HCl but not with HNO3 because

A. Zn acts as an oxidising agent when it reacts with HNO3
B. HNO3 is a weaker acid than H2SO4 and HCl
C.In electrochemical series, Zn is above hydrogen
D. NO3– is reduced in preference to hydronium ion
Answer: (d)

  1. A compound of Xe and F is found to have 53.5% of Xe. What is the oxidation number of Xe in this compound?

A. -4
B. 0
C. +4
D. +6
Answer: (d)

  1. A solution contains Fe2+, Fe3+ and I– ions. This solution was treated with iodine at 35oC. Eo for Fe3+/Fe2+ is 0.77V and Eo for I2/2I– = 0.536V. The favourable redox reaction is

A. I2 will be reduced to I–
B. there will be no redox reaction
C. I– will be oxidised to I2
D. Fe2+ will be oxidised to Fe3+
Answer: (c)

37
  1. One mole of N2H4 loses 10 moles of electrons to form a new compound y. Assuming that all nitrogen appears in the new compound, what is the oxidation state of nitrogen in y.

A. -1
B. -3
C. +3
D. +5
Answer: (c)

  1. The equivalent mass of oxidising agent in the following reaction is

SO2 + 2H2S → 3S + 2H2O

A. 32
B. 64
C. 16
D. 8
Answer: (c)

  1. In the reaction

3Br2 + 6CO32- + 3H2O → 5Br– + BrO3– + 6HCO3–

A. bromine is oxidised and carbonate is reduced
B. bromine is reduced and water is oxidised
C. bromine is neither reduced nor oxidised
D. bromine is both reduced and oxidised
Answer: (d)

  1. Which of the following cannot function as an oxidising agent?

A. I–
B. Si(s)
C. NO3–(aq)
D. Cr2O72-
Answer: (a)

  1. The oxidation number of Pt in [Pt(C2H4)Cl3]– is

A. +1
B. +2
C. +3
D. +4
Answer: (b)

38
  1. Oxygen can be converted into ozone by

A. oxidation at high temperature
B. catalytic oxidation
C. oxidation under high pressure and temperature
D. silent electric discharge
Answer: (d)

2 Which of the following statements is not correct?

A. oxygen is neutral to litmus
B. oxygen is not combustible
C. oxygen supports combustion
D. oxygen is a powerful oxidising agent
Answer: (b)

  1. The violet colour of acidified KMnO4 is decolourised by H2O2. In this reaction H2O2 acts as an

A. oxidising agent
B. reducing agent
C. oxidising as well as reducing agent
D. none of the above
Answer: (b)

  1. Hydrogen peroxide is used as an

A. oxidising agent
B. reducing agent
C. bleaching agent
D. all are correct
Answer: (d)

  1. The oxides of which of the following are neutral in nature?

A. hydrogen
B. halogens
C. alkali metals
D. all the above
Answer: (a)

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39
  1. If the standard free energy change for a reaction is 1.546 kJ/mol at 500oC then the value of the standard equilibrium constant for the reaction is

A. antilog (0.105)
B. antilog (-0.105)
C. antilog (0.241)
D. antilog (-0.241)
Answer: (b)

  1. The standard free energy of formation of NO(g) is

A. 84.8 kJ/mol
B. 86.8 kJ/mol
C. 88.8 kJ/mol
D. 90.8 kJ/mol
Answer: (b)

  1. The term R ln KPo is equal to

A. – ∆G
B. – ∆Go
C. – ∆G/T
D. – ∆Go/T
Answer: (d)

  1. If one gram of kerosene liberates 46.0 kJ of heat when it is burned, to what temperature can 0.25g of kerosene raise the temperature of 75 cm3 of water at 25oC?

A. 61.6oC
B. 46.0oC
C. 66.1oC
D. 64.0oC
Answer: (a)

  1. Which of the following statements regarding entropy is not true?

A. S (monoclinic) > S (rhombic)
B. C (diamond) > C (graphite)
C. H2O(g) > H2O(l)
D. O3(g) > O2(g)
Answer: (b)

40
  1. Which of the following is expressed to have the largest bond dissociation enthalpy?

A. HF
B. HCl
C HBr
D. HI
Answer: (a)

  1. During an isothermal expansion of an ideal gas which of the following is true for the gas?

A. enthalpy decreases
B. entropy decreases
C. enthalpy remains constant
D. entropy remains constant
Answer: (c)

  1. For a spontaneous process, the change in Gibbs function is equal to the

A. the heat content of the system
B. entropy change of the system
C. work of expansion
D. useful work
Answer: (d)

  1. Which of the following is an extensive property?

A. surface area
B. pressure
C. molar volume
D. concentration
Answer: (a)

  1. Which of the following is a state function?

A. q
B. w
C. qrev/T
D. qw
Answer: (c)

41

Acetamide can be converted to methenamine by which of the following reactions?

  1. Stephen’s reaction
  2. Hoffmann bromamide reaction
  3. Carbylamine reaction
  4. Gabriel phthalimide synthesis

Answer: (2)

  1. An aldehyde on reaction with primary amine forms

  2. ketone

  3. Schiff’s base

  4. aromatic acid

  5. carboxylic acid

Answer: (2)

  1. Benzene-diazonium chloride on reaction with phenol in weakly basic medium gives

  2. Diphenyl ether

  3. p-hydroxyazobenzene

  4. Chlorobenzene

  5. Benzene

Answer: (2)

  1. Which one of the following does not contain the -COOH group?

  2. Picric acid

  3. Aspirin

  4. Benzoic acid

  5. Ethanoic acid

Answer: (1)

  1. C3H9N can have how many structural isomers?

  2. 2

  3. 3

  4. 4

  5. 5

Answer: (3)