Important Selected Chemistry Model Question For NEET& JEE

IMPORTANT SELECTED MODEL QUESTION FOR NEET, Chemistry neet exam model question paper, neet exam question paper, neet model paper, neet mode...

IMPORTANT SELECTED MODEL QUESTION FOR NEET,Chemistry neet exam model question paper, neet exam question paper, neet model paper, neet model test, neet mcq

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Q1.On heating one end of a piece of a metal, the other end becomes hot because of

a)Resistance of the metal

b)Mobility of atoms in the metal

c)Energized electrons moving to the other end

d)Minor perturbation in the energy of atoms

Q2. A device that converts energy of combustion of the fuels like hydrogen and methane, directly into electrical energy is known as

(a)Electrolytic cell(b)Dynamo

(c)Ni-Cd cell (d) Fuel cell

Q3. Consider the following relations for emf of aelectrochemical cell

(i) Emf of cell =(Oxidation potential of anode) –

(Reduction potential of cathode)

(ii) Emf of cell = (Oxidation potential of anode)

+(Reduction potential of cathode)

(iii)emf of cell = (Reduction potential of

anode)+(Reduction potential of cathode)

(iv) emf of cell = (Oxidation potential of anode) –

(Oxidation potential of cathode)

Which of the above relation are correct?

(a) (ii) and (iv)

(b) (iii) and (i)

(c)(i) and (ii)

(d) (iii) and (iv)

Q4. On electrolysis of dilute sulphuric acid using platinum electrodes, the product obtained at the anode will be

(a) Hydrogen

(b) Oxygen

(c)Hydrogen sulphide

(D)Sulphur dioxide

Q5. During the electrolysis of molten sodium chloride, the time required to produce

0.10 mol of chlorine gas using a current of 3 amperes is

a)220 minumtes(b)330 monutes

(c)55 minutes(d) 110 minutes

Q6. An electric current is passed through silver nitrate solution using silvern electrodes. 10.79 g of silver was found to be deposited on the cathode if the same amount of sulphate solution using copper electrodes, the weight of copper deposited onthe cathode is

(a)6.4g (b) 2.3 g

(c)12.8 g (d) 3.2g

Q7. An increase in equilvalent conductance of a

strong electrolyte with dilution is mainly due to:

(a) Increase in ionic mobility of ions

(b) 100 % ionization of electrolyte at normal

dilution

(c) Increase in both i.e. number of ions and ionic

mobility of ions

(d) Increase in number of ions

Q8. The ionic conductance of Ba²⁺ and Cl^- are respectively 127 and 76 ohm-1 cm2 at infinite dilution. The equivalent conductance (in ohm^-1 cm²) of BaCl₂ at infinite dilution will be :

(a)139.5 (b) 203

(c)279 (d) 101.5

Q9. At 25⁰C molar conductance of 0.1 molar aqueous solution of ammonium hydroxide is 9.54 ohm^-1 cm² mol^-1 and at infinite dilution its molar conductance is 238 ohm^-1 cm² mol^-1 .The degree or ionization of ammonium hydroxide at the same concentration an temperature is

(a) 20.800% (b) 4.008%

(c)40.800% (d) 2.080%

Q10.How enzymes increases the rate of reactions

(a) By lowering activation energy

(b) By increasing activation energy

(c) By changing equilibrium constant

(d) By forming enzyme substrate complex

Q11 . A chemical reaction is catalyzed by a catalyst X.Hence X

(a) Reduces enthalpy of the reaction

(b) Decreases rate constant of the reaction

(c) Increases activation energy of the reaction

(d) Does not affect equilibrium constant of the

reaction

Q12. In a reaction, A +B -àProduct,

 rate is doubled when the concentration of B is

doubled, and rate increases by a factor of 8 when the concentration of both the reactants (A and B) are doubled, rate law for the reaction can be written as:

(a) Rate = K [A] [B]2

(b) Rate = k[A]2[B]2

(c)Rate =k [A]2[B]2

(d) Rate =k[A]2[B]

Q13. For a reaction between A and B the order with respect to A is 2 and the order with respect to B is 3. The concentrations of both A and B are doubled, the rate will increase by a factor of

(a) 10 (b) 12

(c)16 (d) 32

Q14. The rate of a first order reaction is 0.04 mol^-1s^-1 at 10 seconds and 0.03 mol^-1 s^-1 of 20 seconds after initiation of the reaction. The half-life period of the reaction is

(a) 24.1 s (b) 34.1s

(c)44.1s (d) 54.1s

Q15. A first order reaction has a specific reaction rate of 10^-2 sec^-1. How much time will it take for 20g of the reactant to reduce to 5g ?

(a) 138.6 sec(b) 346.5sec

(c)693.0sec (d) 238.6 sec

Q16. When a few typical solutes are separated by a particular selective memberane such as protein particles, blood corpuscles, this process is called

(a) Transpiration    (b) Endosmosis

(c)Dialysis               (d) Diffusion

Q17. Which one of the following method is commonly used method for destruction of colloid?

(a) Dialysis

(b)Condensation

(c)Filteration by animal membrane

(d) By adding electrolyte

Q18.The catalytic activity of transitions metals and their compounds is describe mainly due to

(a) Their magnetic behavior

(b) Their unfilled d-orbitals

(c)Their ability to adopt variable oxidation states

(d) Their chemical reactivity

Q19. Fog is colloidal solution of

(a) Liquid in gas

(b) Gas is liquid

(c) Solid in gas

(d) Gas in gas

Q20. For adsorption of a gas on a solid, the plot of log x/m versus log P is linear with slope equal to (n being whole number )

(a) K (b) log k

(c)n (d) 1/n

Q21. The Langmuir adsorption isotherm is deduced using the assumption

(a) The adsorption sites are equivalent in their ability to adsorb the particles

(b) The heat of adsorption varies with coverage

(c) The adsorbed molecules interact with each other

(d) The adsorption takes place in multilayers

Q22. Method used for obtaining highly pure silicon used as a semiconductor material, is

(a)Oxidation

(b)Electrochemical

(c)Crystallization

(d) Zone refining

Q23. Which one of the following is a mineral of

iron ?

(a) Malachite (b) Cassiterite

(b) Pyrolusite (d) Magnetite

Q24. Roasting of sulphides gives the gas X as a

byproduct. This is a colourless gas with choking

smell of brunt sulphur and causes great damage to respiratory organs as a result of acid rain. Its

aqueous solution is acidic, acts as a reducing agent and its acid has never been isolated.

The gas X is

(a) CO2 (b) SO3

(c)H2S (d) SO2

Q25. Hypo is used in photography to

(a) Reduce AgBr grains to metallic silver

(b) Convert metallic silver to salt

(c) Remove undercomposed silver bromide as a soluble complex

(d) Remove reduced silver

Q26. Which of the following metal evolves hydrogen on reacting with cold dilute

HNO3?

(a)Mg              (b) AI

(c)Fe                (d) Cu

Q27. Which of the following statement is not correct for nitrogen?

(a) Its electronegativity is very high

(b) D-orbitals are available for bonding

(c) It is typical non-metal

(d) Its molecular size is small

Q28. Basicity of ortho phosphoric acid is

(a) 2 (b) 3

(c)4 (d) 5

Q29. Strongest hydrogen bonding is shown by

(a) Water (b) ammonia

(c)hydrogen fluoride

(d) hydrogen sulphide.

Q30.Elements of which of the following groups will form anions most readily?

(a) Oxygen family

(b) Nitrogen family

(c)Halogens

(d) Alkali metals

Q31. A solution of potassium bromide is treated with each of the following. Which onewould liberate bromine?

(a) Hydrogen iodide

(b) Sulphur dioxide

(c)Chlorine

(d) Iodine

Q32. Which of the following

fluorides does not exist?

(a) NF₅ (b) PF₅

(c)AsF₅ (d) SbF₅.

Q33. Brown ring test is used to detect

(a) Iodine (b) Nitrate

(c)Iron (d) Bromide

Q34. The acid which has a peroxy linkage is

(a) Sulphuric acid

(b) Pyrosulphuric acid

(c) Dithionic acid

(d) Caro’s acid

Q35. Repeated use of which one of the following

fertilizers would increase the acidity of the soil?

(a) Urea

(b) Superphosphate of lime

(c)Ammonium sulphate

(d) potassium nitrate

Q36. During its reactions, ozone

(a) Can only combine with hydrogen atoms

(b) Accepts electrons

(c) Loses electrons

(d) Shows the role of electrons to be irrelevant

Q37.which one of the following statement is not

true?

(a) Among halide ions, iodide is the most powerful reducing agent

(b) Fluoride is the only halogen that does not show a variable oxidation state.

c) HOCl is a stronger acid than HOBr.

(d) HF is a stronger acid than HCI

Q38. Which one of the following is responsible for depletion of the ozone layer in the upper strata of the atmosphere?

(a)Polyhalogens(b)Ferrocene

(c)Fullerenes (d) Freons

Q39. Among K, Ca, Fe and Zn, the element which can form more than one binary compound with chlorine is

(a) Fe (b) Zn

(c)K (d) Ca

Q40. In which of the following molecules are all

the bonds are not equal?

(a) NF₃ (b) CIF₃

(c)BF₃ (d) AIF₃

Q41. Among the followingwhich is the strongest

oxidizing agent?

(a) Br₂ (b) I₂

(c)Cl₂ (d) F₂

Q42. Which is the strongest acid in the following?

(a) HClO₃ (b) HClO₄

(c)H₂SO₃ (d) H₂SO₄

Q43. Which of the following is a polar molecule?

(a) SF₄ (b) SiF₄

(c)XeF₄ (d) BF₃

Q44. PCl₃ is reacts with water to form

(a) PH₃ (b) H₃PO₃,HCl

(c)POCl₃ (d) H₃PO₄

Q45.Which one of the following substance is used in the laboratory for fast drying of neutral gases?

(a) Phosphorus pentoxide

(b) Active charcoal

(c)Anhydrous calcium chloride

(d) Na₃PO₄

Q46. H₃PO₂ is the molecular formula of an acid of phosphorus. Its name and basicity resepectively are

(a)Phosphorus acid and two                         (b)Hypophosphorus acid and two

(c)Hypophosphorous acid and one

(d)Hypophosphoric acid and two

Q47.A one litre flask is full of brown bromine vapour. The intensity of brown colour of vapour will not decrease appreciably on adding will not decrease appreciably on adding to the flask some

(a) Pieces of marble

(b) animal charcoal powder

(c)carbon tetrachloride

(d) carbon disulphide

Q48. Which of the following statement is true?

(a) Silicon exhibits 4 coordination number in its

compound.

(b) Bond energy of F2 is less than Cl2

(c) Mn(III) oxidation state is more stable than Mn(II) in aqueous state.

(d) Elements of 15th group shows only + 3 and +5 oxidation states.

Q49.Which is the correct statement for the given acids?

(a)Phosphinic acid is a diprotic acid while

phosphonic acid is a monoprotic acid

(b)Phosphinic acid is a monoprotic acid while

phosphonic acid is a diprotic acid

(c)Both are triprotic acids

(d)Both are diprotic acids

Q50. It is possible to obtain oxygen from air by fractional distillation because

(a)Oxygen is in a different group of the periodic table from nitrogen

(b)Oxygen is more reactive than nitrogen

(c)Oxygen has higher b.p than nitrogen

(d)Oxygen has a lower density than nitrogen.

Q51.Oxidation of thiosulphate by iodide gives.

(a)Tetrahionate ion

(b)Sulphide ion

(c)Sulphate ion

(d)Sulphite ion

Q52. Which of the following does not give oxygen on heating?

(a)Zn(CIO₃)₂ (b)K₂Cr₂O₇

(C)(NH₄)2Cr₂O₇ (d) KCIO₃

Q53. Among the following the correct order of acidity is

(a)HCIO3 < HCIO4 <HCIO2 <HCIO

(b)HCIO < HCIO2 <HCIO3 <HCIO4

(c)HCIO2 <HCIO <HCIO3 <HCIO4

(d)HCIO4 <HCIO2 <HCIO <HCIO2

Q54. Which of the following statement concerning lanthanide elements is false?

(a)All lanthanides are highly dense metals

(b)More characteristic oxidation state of lanthanide elements is +3

(c)Lanthanides are separated from one another by ion exchange method

(d)Ionic radii of trivalent lanthanides steadily increase with increase in the atomic number.

Q55. To protect iron against corrosion, the most durable metal plating on it, is

(a)Copper plating

(b)Zinc plating

(c)Nickel plating

(d)Tin plating

Q56.which one of the following elements shows

maximum number of different oxidation states in its compounds?

(a)Eu (b) La

(c)Gd (d) Am

Q57.Which of the following statement about the

interstitial compounds is incorrect?

(a)They are chemically reactive.

(b)They are much harder then the pure metal.

(c)They have higher melting points than the pure metal.

d)They retain metallic conductivity.

Q58.The reason for greater range of oxidation states in actinoids is attributed to:

(a)Actinoid contraction

(b)5f,6d and 7s levels having comparable energies

(c)4f and 5d levels being close in energies

(d)The radioactive nature of actinoids

Q59.Identify the following statement among the following

(a)Lanthanoid contraction is the accumulation of

successive shrinkages.

(b)As a result of lanthanoid contraction, the properties of 4d series of the transition elements have no similarties with the 5d series of elements.

(c)Shielding power of 4f electrons is quite weak.

(d)There is a decrease in the radii of the atoms or ions as one proceeds from La to Lu.

Q60. Which one of the following statements is

correct when SO₂ is passed through acidified K₂Cr₂O₇ solution?

(a)The solution turns blue

(b)The solution is decolourized

(c)SO2 is reduced

(d)Green Cr2(SO4)3 is formed

Q61. More number of oxidation states are exhibited by the actinoids than by the

lanthanoids. The main reason for this is

(a)More active nature of the actinoids

(b)More energy difference between 5f and 6d orbitals than that between 4f and 5d orbitals

(c)Lesser energy difference between 5f and 6d orbitals than that between 4f and 5d orbitals

(d)Greater metallic character of the lanthanoids than that of the corresponding actinoids

Q62.Sc (Z=21) is a transition element but Zn (Z=30) is not because

(a)Both Sc and Zn do not exhibit variable oxidation states

(b)Both Sc³⁺ and Zn²⁺ ions are colourless and form white compounds

(c)In case of Sc, 3d orbitals are partially filled but in Zn these are completely filled

(d)Last electron is assumed to be added to 4s level in case of Zn

Q63. Industrial preparation of chloroform employs acetone and

(a)Phosgene

(b) Calcium hypochlorite

(c)Chlorine gas

(d) Sodium chloride

Q64. An organic compound A(C4H9Cl) on reaction with Na/diethyl ether gives a

hydrocarbon which on monichlorination gives only one chloro derivative, then A is

(a)Tert –butyl chlorine

(b) sec-butyl chloride

(c)isobutyl chloride

(d) n-butyl chloridE

Q65. Which of the following is correct?

(a)Cycloheptane is an

aromatic compound

(b)Diastase is an enzyme

(c)Acetophenone is an ether

(d)All of the above

Q67. Number of isomeric alcohols of molecular formula C₆H₁₀O  which give positive

iodoform test is

(a)Three (b) four

(c)five (d) two

Q68. What is formed when a primary alcohol undergoes catalytic dehydrogenation?

(a) Aldehyde (b) Ketone

(c)Alkene (d) Acid

Q69. Ethanol and dimethyl ether form a part of

functional isomers. The boiling point of ethanol is higher than that of dimethyl ether, due to the presence of

(a)H- bonding in ethanol

(b)H- bonding in dimethyl ether

(c)CH₃ group in ethanol

(d)CH₃ group in dimethyl ether

Q70.Aldehydes and ketones will not form crystalline derivatives with

(a)Sodium bisulphate

(b)phenylhydrazine

(c)semicarbazide hydrochloride

(d) Dihydrogen sodium phosphate.

---

Answer

Q1Ans (c) Because of energized electrons moving to the other end

Q2Ans(d) Is known as fuel cell.

Q3Ans (a) (ii) and (iv) are correct realations

Q4Ans (b) Obtained product is Oxygen.

Q5. Ans (d) Q6.D

Q7.Ans (a) strong electrolytes are completely ionized at all concentrations. On increasing dilution the no. of ions remains same but the ionic mobility and equivalent conduction increases.

Q10. Ans (a) Enzymes act like catalyst in biochemical reactions. Presence of an enzyme increases the rate of reaction by lowering the activation energy of the reactant.

Q11.Ans (d) A catalyst affects equally for both forward and backward reactions. So it does not affect equilibrium constant of reaction.

Q12.d

Q13. Ans (d) Rate = k[A]2[B]3

When concentrations of both A and B are doubled then

Rate =k[2A]2[2B]3=32k [A]2[B]3[22 x23=32]

So, rate will increase by a factor of 32.

Q14.a Q15.a Q16.c

Q17.Ans (b) Condensation method is used for destruction.

Q18.Ans (c) Adopt the ability of variable oxidation energy.

Q19.Ans (a) Fog is colloidal solution of liquid in gas.

Q20.d

Q21. Ans.(a) Langmuir adsorption isotherm is based on the assumption that every adsorption site is equivalent and whether sites are not occupied or occupied the ability of a particle to bind is independent.

Q22.d

Q23. Ans(d)Magnetitie (Fe2O3) is a mineral of iron.

Q24.d

Q25. Ans (c) Hypo is used in photography to remove under composed silver Bromide as soluble complex.

Q26.Ans (a) Magnesium and manganese are the metals that produce hydrogen with dilute nitric acid because they are electropositive in nature

Mg +2HNO3------ Mg(NO3)2 +H2

Q27Ans (b) d-orbitals are available for bonding is not correct for nitrogen.

Q28.b

Q29. Ans (c) Strongest hydrogen bonding is shown by Hydrogen Fluoride

Q30. Ans (c) As halogens have seven electrons (ns2np2) in the valence shell, they have a strong tendency to acquire the nearest inert gas configuration by gaining an electron from the metallic atom and form halide ions easily.

Q31. (a) Hydrogen iodide has the liberate bromine.

Q32. Ans (a) NF5 does not exist because the size of nitrogen atom is very small

Q33. Ans (b) Brown ring test is used to detect nitrate.

Q34.d Q35.c

Q36 Ans (a) Ozone can only combine with hydrogen atoms.

Q37.d Q38.d Q39.a

Q40. Ans (b) CIF3 molecules all bond are not equal.

Q41.Ans (d) F2 is strongest oxidizing agent.

Q42. Ans (b) Order of acidic strength in strong acid are HCIO4 > H2SO4 > HCIO3 >H2SO3

Q43. Ans (a) SF4 is a polar molecule.

Q44. Ans (b) PCl3 +3H2O-----H3PO3+ 3HCl

Q45. Ans (a) phosphorus pentoxide has great affinity for water. It forms ortho phosphoric acid on absorbing water.

P4O10 +6H2O------- 4H3PO4

It is used as a powerful dehydrating or drying agent.

Q46. Ans (c) H3PO2 is named as hypophosphorus acid. As it contains only one P ---OH group, so its basicity is one

Q47. Ans (a) Due to absence of reaction between marble and bromine

Q48. Ans (b)Fluorine is more reactive than chlorine. So bond energy of chlorine is greater than fluorine.

Q49.b

Q50. Ans (c) By use of the joule-Thomson effect air is liquefied (cooling by expansion of the gas). Water vapour and CO2 are removed by solidification. The remaing constituents of liquid air (liquid oxygen and liquid nitrogen ) are seprated by means of fractional distillation (b.p of O2 = - 1830C :b.p of N2= -195.80C)

Q51.a 

Q52.c

Q53. Ans (b) Acidic strength increases as the oxidation number of central atom increases

Q54. Ans (d) Ionic radii of trivalent lanthanides steadily increases with increase in atomic number

Q55.Ans (c)A layer of oxide is formed on the surface of nickel, which protects nickel, below it and iron underneath it.

Q56.Ans (d) Oxidation states shown by elements are as follows:

La = +3

Eu and Gd = +2 and +3

Am = +2 +3 +4 +5 and +6

Due to its longer size and low ionization energy am shows maximum number of different ixidation state.

Q57. Ans (a) Interstitial compounds are obtained when small atoms like H,B,C,N etc. fit into the interstitial space of lattice metals. These retain metallic conductivity. These resemble the parent metal in chemical properties like hardness, Ans (b)Minimum energy gap between 5f, 6d and 7s subshell. That’s why e- excitation will be easier.melting point etc.

Q58. Ans (b)Minimum energy gap between 5f, 6d and 7s subshell. That’s why e- excitation will be easier.

Q59.Ans (b) As a result lanthanide contraction, the atomic radii of element of 4d and 5d come closer, so the properties of 4d and 5d transition element shows the similarities. The regular decrease in the radii of lanthanide ions from La3+ to Lu3+ is known as lanthanides contraction.

It is due to greater effect of the increased nuclear charge than that of screening effect (shielding effect).

Q60. Ans (d

Q61. Ans (c) The 5f –orbitals extend into space beyond the 6s and 6p-orbitals and participate in bonding. This is in direct contrast to the lanthanides where the 4f-orbitals are buried

deep inside in the atom, totally shielded by outer orbitals and thus unable to take part in bonding.

Q62 Ans (c) A transition element must have incomplete d-subshell. Zinc have completely filled d-subshell having 3d10 configuration . so do not show properties of transition elements to any appreciable extent except for their ability to form complexes.

Q63.b 

Q64.a 

Q65.(b) 

Q66.(a) 

Q67(b)

Q68 Ans (a) Primary alcohol undergoes catalytic dehydrogenation to give aldehyde.

Q69. Ans (c) Formation of a yellow precipitate on heating a compound with an alkaline solution of iodine is known as “iodoform reaction”.

alcohols which posses CH3CH(OH)--- group.

As: C2H3OH +4l2 +NaOH------CHl3+ Nal + HCOONa +H2O

Methyl alcohol does not respond to this test. Idoform test is exhibited by ethyl alcohol, acetaldehyde, acetone, methyl ketones and those

Q70Ans Ans (d) Dihydrogen sodium phosphate (NaH2PO4) does not have a lone pair of electrons on the P-atom. As such it can not act as a nucleophile and does not react with aldehydes and ketones.

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