Chemistry Basic Concepts MCQ

1. The oxidation number of carbon in CH2O is

a. -2
b. +2
c. 0
d. +4
(JEE 1982)

Ans: ( c )

Gaseous - Liquid - Solid States- Multiple Choice Questions

1. Helium atom is two times heavier than a hydrogen molecule. At 298 K, the average kinetic energy of a helium atom is

a. same as that of a hydrogen molecule
b. two times that of a hydrogen molecule
c. four times that of a hydrogen molecule
d. half that of a hydrogen molecule
(JEE 1982)

Answer: (a)

2. among the following, the molecule that is linear is

a. CO2
b. NO2
c. SO2
d. ClO2
(JEE 1982)

ans : (a)

CO2 is a linear molecule

3. A liquid is in equilibrium with its vapour at its boiling point. On average, the molecules in the two phases have equal:

a. inter-molecular forces
b. potential energy
c. kinetic energy
d. temperature
(JEE 1984)

Answer (d)

4. Rate of diffusion of a gas is:

a. directly proportional to its density
b. directly proportional t its molecular weight
c. directly proportional to the square root of its molecular weight
d. indirectly proportional to the square root of its molecular weight
(JEE 1985)

Answer (d)

5. the average velocity of an ideal gas molecule at 27°C is 0.3 m/s. the average speed at 927°C will be:

a. 0.6 m/s
b. 0.3 m/s
c. 0.9 m/s
d. 3.0 m/s
(JEE 1986)

Answer: (a)

Atomic Structure - Multiple Choice Questions

1. Any p-orbital can accommodate up to

a. four electrons
b. two electrons in parallel groups
c. six electrons
d. two electrons with opposite spins
(JEE 1983)

Answer ( c )

2. the principal quantum number of an atom is related to the

a. size of the orbital
b. spin angular momentum
c. orbital angular momentum
d. orientation of the orbital in space
(JEE 1983)

Answer: (a)

3. Correct set of four quantum numbers forhte valence (outmost) electron of rubidium 9Z = 37) is:

a. 5,0,0,+1/2
b. 5,1,0, +1/2
c. 5,1,1,+1/2
d. 6,0,0,+1/2
(JEE 1984)

Answer: (a)

4. Bohr model can explain:

a. the spectrum of hydrogen atom only
b. spectrum of an atom or ion containing one electron only.
c. the spectrum o hydrogen molecule
d. the solar spectrum
(JEE 1985)

Ans: (b)

5. Which one of the following sets of quantum numbers(n,l,ml, ms) represents as impossible arrangement?
a. 3,2,-2,1/2
b. 4,0,0,1/2
c. 3,2,-3,1/2
d. 5,3,0,-1/2
(JEE 1986)

Answe ( c )

Periodic Properties - Multiple Choice Questions

1. The element with the highest first ionization potential is

a. boron
b. carbon
c. nitrogen
d. oxygen
(jee 1982)

Answer: ( c )

Chemical Bonding - Multiple Choice Questions

1. The ion that isoelectronic with CO is

a. CN^-
b. O2⁺
c. O2^-
d. N2⁺
(JEE 1982)

ans: (a)

isoelectronic means same number of electrons

2. carbon tetrachloride has no net dipole moment because of

a. its planar structure
b. its regular tetrahedral structure
c. similar sizes of carbon and chlorine atoms
d. similar electron affinities of carbon and chlorine
(JEE 1983)

ans (b)

3. which one among the following does not have the hydrogen bond?

a. phenol
b. liquid NH3
c. water
d. liquid HCl
(JEE 1983)

Ans: (d)

4. the types of bonds present in CuSO4.5H2O are only

a. electrovalent and covalent
b. electrovalent and coordinate covalent
c. electrovalent, covalent and coordinate covalent
d. covalent and coordinate covalent

5. On hybridization of one s and one p orbitals we get:

a.two mutually perpendicular orbitals
b. two orbital at 180°
c. four orbitals directed tetrahedrally
d. three orbital in a plane
(JEE 1984)

Answer: (b)

6. the molecule having one unpaired electron is:

a. NO
b. CO
c. CN^-
d. O2
(JEE 1985)

Ans: (a)

7. The bond between two identical non-metal atoms has a pair of electrons:

a. unequally shared between the two.
b.transferred fully from one atom to another
c. with identical spins
d. equally shared between them
(JEE 1986)

Ans: (d)

8. the hydrogen bond is strongest in:

a. O-H…S
b. S-H…O
c. F-H…S
d. F-H...O
(JEE 1986)

Answer: ( c )

9. The hybridization of sulphur dioxide is:

a. sp
b. sp²
c. dsp²
d. sp³
(JEE 1986)

answer (b)

10. The bonds present in N2O5 are ______

a. only ionic
b. covalent and coordinate
c. only covalent
d. covalent and ionic
(JEE 1986)

ans: (b)

Chemical Equilibrium - Multiple Choice Questions

One Answer only

1. The ion that cannot be precipitated by both HCl and H2S is

a. Pb²⁺
b. Ag⁺
c. Cu⁺
d. Sn²⁺

(JEE 1982)

Ans: (d)

2. A certain buffer solution contains equal concentration of X^- and HX. The Kb for X^- is 10^-10. The pH of the buffer is:

a. 4
b. 7
c. 10
d. 14
(JEE 1984)

ans: a

3. A certain weak acid has a dissociation constant of 1.0*10^-4. The equilibrium constant for its reaction with a strong base is:

a. 1.0*10^-4
b. 1.0*10^-10
c. 1.0*10¹⁰
d. 1.0*10¹⁴
(JEE 1984)

Answer: ( c)

4. An example of a reversible reaction is:
(JEE 1985)

5. The conjugate acid of NH₂^- is:

a. NH3
b. NH4OH
c. NH₄⁺
d. N2H4
(JEE 1985)

Answer: (a)

6. the compound that is not a Lewis acid is:

a. BF3
b. AlCl3
c. BeCl2
d. SnCl4
(JEE 1985)

Answer: (c )

BeCl2 cannot accept a lone pair of electrons.


7. the compound whose 0.1 M solution is basic is:

a. ammonium acetate]
b. ammonium chloride
c. Ammonium sulphate
d. sodium acetate
(JEE 1986)

Answer (d)

Electrochemistry - MCQ - One Answer Only

1. Faraday’s laws of electrolysis are related to the

a. atomic number of the cation.
b. atomic number of the anion.
c. equivalent weight of the electrolyte
d. speed of the cation
(JEE 1983)

Ans: ©

2. A solution containing one mole for litre each of Cu(NO3)2, AgNO3, Hg2(NO3)2 and Mg(NO3)2 is electrolysed using inert electrodes.
Standard electrode potentials in volts (reduction potentials) are:

Ag⁺| Ag = 0.80
Hg2²⁺ |Hg = 0.79
Cu²⁺|Cu = 0.34
Mg²⁺|Mg = -2.37

With increasing voltage, the sequence of deposition of metals on the cathode will be:
(JEE

a. Ag,Hg,Cu, Mg
b. Mg,Cu,Hg,Ag
c. Ag,Hg, Cu
d. Cu,Hg, Ag

Ans: ( C )


3. The electric charge or electrode deposition of one gram equivalent of a substance is:

a. one ampere for one second
b. 96,500 coulombs per second
c. one ampere for one hour
d. charge on one mole of electrons
(JEE 1984)

ans (d)

4. The reaction ½ H2(g) + AgCl(s) = H⁺(aq) + Cl^-
(aq) +Ag(s) occurs in the galvanic cell:

a. Ag|AgCl(s) |KCl(soln) |AgNO3(soln) |Ag
b.Pt|H2(g) |HCl(soln) |AgNO3(soln) |Ag
c. Pt|H2(g) |HCl(soln) |AgCl(s) |Ag
d. Pt|H2(g) |KCl(soln) |AgCl(s) |Ag
(JEE 1985)

Ans: c
In cell c reactions occurring are

AgCl(s) + e^- -> Ag(s) + Cl^-(aq)
½ H2(g) -> H⁺ (aq) + e^-

adding ½ H2(g) + AgCl(s) = H⁺(aq) + Cl^-
(aq) +Ag(s)

Solutions - MCQ - One answer only

1. For a dilute solution, Raoult’s law states that:

a. the lowering of vapour pressure is equal to the mole fraction of solute
b. the relative lowering of vapour pressure is equal to the mole fraction of solute
c. the relative lowering of vapour pressure is proportional amount of solute in the solution.
d. the vapour pressure of the solution is equal to the mole fraction of solvent.
(JEE 1985)

Ans: b

Raoult’s law: The partial pressure of the vapours of a constituent is proportional to the mole fraction of the latter in the solution.

2. The pair of compounds which cannot exist together in solution is:
a. NaHCO3 and NaOH
b. Na2CO3 and NaHCO3
c. Na2CO3 and NaOH
d. NaHCO3 and NaCl
(JEE 1986)

Answer (a)

3. One molal solution is one that contains one mole of a solute in:

a. 1000 g of the solvent
b. one litre of solvent
c. one litre of the solution
d. 22.4 litres of the solution
(JEE 1986)

answer (a)

Chemical Kinetics - MCQ - One Answer only

1. The rate constant of a first order reaction depends on the

a. temperature
b. time
c. concentration of the reactant
d. concentration of the product
(JEE 1983)

Answer (a)

2. a catalyst is a substance which

a. increases the equilibrium concentration of the product
b. increases the equilibrium constant of the reaction.
c. supplies energy to the reaction
d. shortens the time to reach equilibrium
(JEE 1983)

Answer: (d)

Nuclear Chemistry - MCQ - One answer only

1. Rutherford’s scattering experiment is related to the size of the

a. atom
b. nucleus
c. electron
d. neutron

Answer (b)

2. Heavy water is

a. H₂¹⁸O
b. D₂O
c. water obtained by repeated distillation
d. water at 4°C

(JEE 1983)

Ans: (b)

3. The radiation from a naturally occurring radioactive substance, as seen after deflection by a magnetic field in one direction, are:

a. definitely alpha rays
b. definitely beta rays
c. both alpha and beta rays
d. either alpha or beta rays
(JEE 1984)

Ans: (d)

Both alpha and beta rays are deflected by magnetic field.

4. The increasing order (lowest) first for the values of e/m (charge/mass) for electron e, proton p, neutron n and alpha particle α is:

a. n, α,p,e
b. e,p,n, α
c. n,p,e, α
d. n,p, α,e
(JEE 1984)

Ans: a

Reason: Charge for neutron is zero hence e/m = 0 for neutron.
For alpha particle> It has two protons and two neutrons. Hence charge is equal to charge of two protons and mass is equal to mass of 4 protons. Hence in comparison to proton e/m, alpha particle’s e/m is 2e/4m which is equal to 0.5e/m. Electron has the same charge as proton but of different sign, but its mass is very low. Hence compared to proton its e/m is very high.

5. The radius of an atomic nucleus is of the order of:

a. 10^-10cm
b. 10^-8cm
c. 10^-13cm
d.10^-15cm
(JEE 1985)

Answer: ( c)

6. electromagnetic radiation with maximum wavelength

a. infrared
b. radiowave
c. ultraviolet
d. X-ray
(JEE 1985)

Answer (b)

Wavelength of radio waves is greater than infraredwaves.

7. Rutherford’s alpha particle scattering experiment eventually led to the conclusion that

a. mass and energy are related.
b. electrons occupy space around the nucleus.
c. neutrons are buried deep in the nucleus.
d. the point of impact with matter can be precisely determined.
(JEE 1986)

answer (b)

8. The ratio of energy of a photon of 2000 A° wavelength radiation to that of 4000A° is:

a. ¼
b. 4
c ½
d. 2
(JEE 1986)

Answer (d)

9. The half life period of a radioactive element is 140 days. After 560 days, one gram of the element will reduce to:

a. 1/16 g
b. 1/8 g
c. ¼ g
d. ½ g
(JEE 1986)
answer: (a)

Gaseous, Liquid, Solid State - True or False Type Questions

1. When a liquid and its vapour are in equilibrium and the pressure is suddenly decreased, cooling occurs. (JEE 1984)

True

Reason: The decrease in pressure results in further evaporation of the liquid into gaseous phase. The energy required for this is realized from the liquid itself which causes a decrease in temperature.

2. Kinetic energy of molecules is zero at 0°C. (JEE 1985)

Ans: False

The equation relating energy of molecules to temperature is in absolute temperature and not centigrade temperature.

3. A gas in a closed container will exert much higher pressure due to gravity at the bottom than at the top. (JEE 1985)

False.

It is equal in all directions.

4. Heat capacity of a diatomic gas is higher than that of a monatomic gas. (JEE 1985)
True

Diatomic gas has translational, rotational, and vibrational energies. Monatomic gas has only translational energy.

5. In the van der Waals equation,

[p + n²a/V²][V-nb] = nRT

the constant ‘a’ reflects the actual volume of the gas molecules.

False

Reason: In the equation ‘a’ is a measure of the forces of attraction between gaseous molecules and b is a measure of effective volume occupied the molecules of 1 mol of a gas.

Atomic Structure - True or False Type Questions

1. The outer electronic configuration of the ground state chromium atom is 3d⁴4s². (JEE 1982)

False

Chromium atomic number is 24.
Its our electronic configuration is 3d⁵4s² .

2. The energy of the electron in the 3d-orbital is less than that in the 4s-orbital in the hydrogen atom. (JEE 1983)

Ans: True. (Think what is the explanation)

Periodic Properties - True or False Type Questions

1. Dispositive zinc exhibits paramagnetism due to loss of two electrons from 3d-orbital of neutral atom. (JEE 1987)

False.

Reason: Zn²⁺ exhibits diamagnetism. Formation of the ion involves loss of two electrons from 4s orbital. The resultant configuration of 10 electrons in 3d orbital does not have unpaired electrons. So it exhibits diamagnetism.

2. In Group IA of alkali metals, the ionization potential decreases down the group. Therefore lithium is a poor reducing agent.

False

Reducing strength is determined by the negative of reduction potential (i.e., oxidation potential) and not by the ionization potential. Lithium is the strongest reducing agent among alkali metals.

3. Both potassium ferrocyanide and potassium ferricyanide are diamagnetic. (JEE 1989)

False

Potassium ferrocyanide is diamagnetic (no unpaired electron) while potassium ferricyanide is paramagnetic (one unpaired electron)

4. The presence of polar bonds in a polyatomic molecule suggests that the molecule has non-zero dipole moment. (JEE 1990)

False

There are polyatomic molecules with polar bonds that have zero dipole moment due to symmetric arrangement of polar bonds.

5. The decreasing order of electron affinity of F,Cl, Br is F>Cl>Br. (JEE 1993)

False

The order is Cl>F>Br. Due to the small size in F atom there is larger electronic repulsion. Hence electron affinity is more in Cl than in F.


6. The basic nature of hydroxides of Group13 (Gr. III B) decreases progressively down the group. (JEE 1993)

False

Basic nature increases as the element becomes more metallic. As one goes down the group metallic character increases.

Chemical Bonding - True or False Type

1. Linear overlap of two atomic p-orbitals leads to a sigma bond. (JEE 1983)

True

2. The H-N-H bond angle in NH3 is greater than the H-As-H bond angle in AsH3.

True

Reason: Repulsion is more in NH3 which makes the bond angle greater than in AsH3.

3. All molecules with polar bonds have dipole moment. (JEE 1985)

False.

Reason; If symmetrical arrangement of atoms is there, there is no dipole moment. Example CCl4.

4. SnCl2 is nonlinear molecule. (JEE 1985)
True

There is a lone pair in the bond. Due to repulsion between Lone pair and bonding pair, the bond angle less than 180°.

5. sp² hybrid orbitals have equal s and p character.

False

sp² hybrid use one s orbital and 2 p orbital for hydridisation. Hence sp² hybrid orbitals have 1/3 s character and 2/3 p character.

6. All the Al-Cl bonds in Al2Cl6 are equivalent. (JEE 1989)

False

The terminal Al-Cl bonds are different from the bridge Al-Cl bonds.

7. Nitric oxide, though an odd electron molecule, is diamagnetic in liquid state. (JEE 1991)

False

In liquid state, some dimerization takes place, but it is only partial. So it is still paramagnetic only.

8. Dipole moment of CH3F is greater than CH3Cl. (JEE 1993)
False

Bond distance is more in CH3Cl and hence more dipole moment.
Dipole moment = charge * distance

Energetics - True or False Types

1. First law of thermodynamics is not adequate in predicting the direction of a process.
(JEE 1982)

True

First law only says increase in internal energy of a system is due to heat transferred to the system and work done on the system. It does not predict the direction of a process.

Chemical Equilibrium - True or False Type Questions

1. If equilibrium constant for the reaction A2 + B2 ↔ 2AB, is K, then for the backward reaction AB ↔ ½ A2 + ½ B2, the equilibrium constant is 1/K. (JEE 1984)

Answer: False

Reason: For A2 + B2 ↔ 2AB,
K = [AB] ²/[A2][B2]

For AB ↔ ½ A2 + ½ B2 equilibrium constant is

= [A2] ^1/2[B2] ^1/2/[AB]

This is not equal to 1/K.

2. Solubility of sodium hydroxide increases with increase in temperature. (JEE 1985).

Answer: False

3. From the solution containing copper (+2) and zinc (+2) ions , copper can be selectively precipitated using sodium sulphide. (JEE 1987)

False

Na2S will produce an alkaline solution, both copper (+2) and zinc (+2) ions would be precipitated.

4. The rate of exothermic reaction increases with increasing temperature. (JEE 1990).

Answer: True
Reason: In general, rate of a reaction increases with increase in temperature which is due to increase in the rate constant of the reaction. As per the Arrhenius equation relating k and T, as temperature increases k increases. (Note: At equilibrium if the temperature is increased, for an exothermic reaction the equilibrium shifts leftward).

Electrochemistry - True or False Questions

1. The dependence of electrode potential for the electrode Mⁿ⁺ |M with conetration under STP conditions is given by the expression:

E = E° + 0.0591 V/n * log₁₀[Mⁿ⁺ |]

(JEE 1993)

False

The factor 0.0591 is applicable when the temperature is 298 K and not 273 K.

Chemical Kinetics - True or False Type Questions

1. For a first order reaction, the rate of the reaction doubles as the concentration of the reactant(s) doubles. (1986)

Answer: True

Reason: For a first order reaction r = k[A].
Where r = rate of reaction
K = reaction constant
[A] = molar concentration of reactant
Hence if concentration doubles r also is doubled,.

2. Catalyst makes reaction more exothermic. (JEE 1987)

Ans: False
Catalyst does not affect the enthalpy of reaction. It affects only the rate of reaction.

Nuclear Chemistry - True - False Type Questions

1. Gamma rays are electromagnetic radiations of wavelengths of 10^-6 to 10^-5 cm. (1983)

Ans: False

2. In β-emission from a nuclues the atomic number of the daughter element decreases by one. (JEE 1990).

Answer: False

In β-emission, number of protons in the nucleus goes up by one.

3. In a given electric field, β-particles are deflected more than α-particles having larger charge. (JEE 1993)

True

The deflection of the particle depends on the acceleration produced in it. The acceleration depends on the force and mass. Thus, in case of electric field it depends on the e/m of the particles. For β-particles, e/m is larger than α-particles because electrons are very very light than He⁺ species. So charge on helium particle is only twice high but mass is very very high.

Nuclear Chemistry - Fill Blanks Type

1. An element under [A,Z]M undergoes an α-emission followed by two successive β-emissions. The element formed is __________ . (JEE 1982)

answer: [A-4, Z]M
Refer:
α-emission
β-emission

2. The number of neutrons in the parent nucleus which gives ¹⁴N on beta emission is __________ . (JEE 1985)

Answer: 8
Reason: One proton increases to give 7 protons of nitrogen. Hence before beta emission there are 8 neutrons and 6 protons.

3. A radio active nucleus decays emitting one alpha and two beta particles; the daughter nucleus is ___________ of the parent. (JEE 1989)

Answer: isotope
Reason; Z is same but A is different.

Surface Chemistry - Fill Blanks Type

1. The absorption of hydrogen by palladium is commonly known as ___________ .
(JEE 1983)

Answer: occlusion

Chemical Kinetics - Fill Blanks Type

1. The rate of chemical change is directly proportional to ______________. (JEE 1985)

Answer: concentration of reactants

2. In the Arrhenius equation, k = A exp(-E₀/RT), A may be termed as the rate constant at ____________ . (JEE 1997)

Answer: Very high temperature or zero activation energy.
As k becomes equal to A in either case.

1. 3 g of a salt of molecular weight 30 is dissolved in 250 g of water. The molality of the solution is _____________ . (JEE 1983)

Answer; 0.4 mol kg^-
Molality (m) = number of moles of solute/kilograms of solvent
0.1 mol salts dissolved in .25 kg of water. So m = 0.1/.25 = 0.4 mol/kg

2. Given that ΔT_f is the depression in freezing point of the solvent in a solution of a non-volatile solute of molality, m, te quantity lim m→0 (ΔT_f/m) is equal to _________________ . (JEE 1994)

Answer: K_f

Electrochemistry - Fill Blanks Type

1. The more ___________________ the standard reduction potential, the __________________ is its ability to displace hydrogen from acids.
(JEE 1986)

Answer: negative, greater

2. The electrolysis of molten sodium hydride liberates ______________ gas at the ____________.

(JEE 1989)

Answer H2, anode

3. When an aqueous solution of sodium fluoride is electrolysed, the gas liberated at the anode is _________________ . (JEE 1997 cp)

Answer: O2

Chemical Equilibrium (Ionic Equilibrium) - Fill Blanks

1. The conjugate base of HSO₄^- in acqueous solution is_____________.

(JEE 19820)

Answer: SO₄^2-

2. The hydrolysis of ethyl acetate in ______________________ medium is a _________ order reaction.

(JEE 1986)

Answer : acidic, first order

3. ____________ acid gives _____________ ion.
(options given: hydrobromic acid, hypobromous. Perbromic, bromide, bormite, perbromate)

(JEE 1988)

Answer: Hydrobromic acid, bromide (*Refer TMH Chemistry IIT 2007-Table 7.1)

4. For a given reversible reaction, at a fixed temperature equilibrium constants Kp and Kc are related by ____________________ .
(JEE 1994)

Answer : Kp = Kc (RT) ^{Δ v}g


4a. Solubility of iodine in water is greatly increased by the addition of iodide ions because of the formation of _______________________. (JEE 1994)

Answer: I3^-,

5. A ten fold increase in pressure on the reaction

N2(g) + 3H2(g) ↔ 2NH3(g) at equilibrium results in _____________ in Kp.

(JEE 1996)

Answer: no change

Reason: Kp of an equilibrium reaction is independent of pressure of the system.

6. For a gaseous reaction 2B → A, the equilibrium constant Kp is _____________ to/than Kc.
(JEE 1997)

Answer: smaller

7. In the reaction I^- + I2 → I3^-, the Lewis acid is _______________ .
(JEE 1997)
Answer: I2

Chemical Energetics - Model Questions - Fill Blanks Type

1. The total energy of one mole of an ideal monatomic gas at 27°C is __________ calories. (JEE 1984)

Answer (3/2)RT = (1.5 mol)[1.987 cal/ (K mol.)](300 K) = 894.15 cal.

2. A system is said to be ___________ , if it can neither exchange matter nor energy with the surroundings. (JEE 1993)

Answer: isolated

3. The heat content of the products is more than that of the reactants in an _____________ reaction. (JEE 1993)

Answer: endothermic

4. When Fe (solid) is dissolved in acqueous hydrochloric acid in a closed vessel, the work done is _________________ . (JEE 1997)

Answer: zero

5. Enthalpy is an ____________ property. (JEE 1997)

Answer: extensive property.

It depends on mass of the substance

Solid, Liquid, Gas Phases - 21 - Fill Blanks Type

1. Cp – Cv for an ideal gas is ____________.
(JEE 1984)

Answer : R
(See page No. 67 H C Verma part 2)

2. The rate of diffusion of gas is ______________________ proportional to the square root of molecular mass.
(JEE 1986)

Answer: inversely
(Graham’s law of diffusion: The rate of diffusion of a gas is inversely proportional to the square root of its density or molar mass.)

3. The value of PV for 5.6 litres of an ideal gas is _________________ RT at STP.
(JEE 1987)

Answer: ¼ or 0.25
1 mole of an ideal gas at STP has a volume of 22.4 litres

4. Eight grams of oxygen and hydrogen at 27°C will have the total kinetic energy in the ratio of __________________.
(JEE 1989)

Answer: 1:16

Reason: For a mixture of gases, in thermal equilibrium, average kinetic energy of all molecules is same.

(½)*m1* v1² = (1/2)*(m2*v2²

Oxygen’s molecular weight is 32 and hence 8 grams will have 8/32 = ¼ moles.
Hydrogen’s molecular weight is 2 and hence 8 grams will have 8/2 = 4 mols

Total kinetic energy of oxygen moleculues = (¼ )* (½)*m1* v1²
Total kinetic energy of hydrogen molecules = 4*(1/2)*(m2*v2²

The ratio will be (1/4)/4 = 1/16 as remaining terms or equal in both cases.

5. The shape of [CH3] ⁺ is ___________________.
(JEE 1990)

Answer: Planar

6. Among N₂0, S0₂, I₃3⁺, I₃^-, the linear species are ____________ and __________ .
(JEE 1997).

Answer: N₂0, I₃3^-

7. A liquid which is permanently supercooled is frequently called as ___________.
(JEE 1997)

Answer: glass

Atomic Structure - 11 - Fill in the Blanks Type

1. The mass of a hydrogen atom is ------------------ kg. (JEE 1982)

answer: 1.66*10^-27 kg

2. When there are two electrons in the same orbital, they have ---------------- spins. (JEE 1982)

Answer: opposite or antiparallel

3. Isotopes of an element differ in the number of ______________ in their nuclei. (JEE 1982)

Anwer: neutrons




4. Elements of same mass number but of different atomic numbers are known as ----------.
(JEE 1983)

Answer: isobars


5. Fill in the blanks choosing appropriate words given with brackets)
the uncertainty principle and the concept of wave nature of matter were proposed by ----------------- and -------------------- respectively
(Heisenberg, Schrodinger, Maxwell, de Broglie)
(JEE 1988)

Answer: Heisenberg, de Broglie

Chemical Bonding - 11 - Fill in the Blanks Type Questions

Fill in the blanks

1. There are ____________________ π (pi) bonds in a nitrogen molecule. (JEE 1982)
Anwer : 2

2. __________ hybrid orbitals of nitrogen are involved in the formation of ammonium ion. (JEE 1982)
Answer sp³

3. The terminal carbon atom in butane is _____________ hybridized. (JEE 1985)
Answer sp³



The shape of [CH3] ⁺ is ------------------------.
(JEE 1990)
Answer: Triangular planar

The valence atomic orbitals of carbon in silver acetylide is _________________.
(JEE 1990)

Answer: sp

IN P4O10, the number of oxygen atoms bonded to each phosphorus atom is ____________ .
(JEE 1992)

Answer: 4

When N2 goes to N2⁺
The N—N bond distance _________ and when O2 goes to )2⁺, the O—O bond distance ______________.

(JEE 1996)
Answer: increases, decreases

Chemical Bonding - 12 - True or False type Questions

State whether the following statements are True or False.

1. Linear overlap of two atomic p-orbitals leads to a sigma bond. (JEE 1983)

True

2. The H-N-H bond angle in NH3 is greater than the H-As-H bond angle in AsH3. (JEE 1984)

True. Repulsion among bonds is more in NH3 and it makes bond angle greater.

3. All molecules with polar bonds have dipole moment. (JEE 1985)

False. Symmetrical molecules will have zero dipole moment.

4. SnCl2 is nonlinear molecule (JEE 1985)

True

5. sp² hybrid orbitals have equal s- and p- character (JEE 1987)

False. One third s and two thirds p.


The presence of polar bonds in a polyatomic molecules suggests that molecule has non-zero dipole moment (JEE 1990)

False. Some polyatomic molecules having polar bonds have zero dipole moment.


H2O molecule is linear. (JEE 1993)

False. It is V-shaped.

The dipole moment of CH3F is greater than that of CH3Cl. (JEE 1993)

False. Dipole moment in CH3F is less than CH3Cl as bond length is shorter in CH3F. Remember the definition of dipole moment from physics.