Olete.in – MCQs, Mock Tests & Government Job Prep | NCERT Class 11 MCQ Questions for Class 11 Chemistry sets 2

Third law of thermodynamics provides a method to evaluate which property?

1. Absolute Energy
2. Absolute Enthalpy
3. Absolute Entropy
4. Absolute Free Energy

✅ Correct Answer: 3

One mole of which of the following has the highest entropy?

1. Liquid Nitrogen
2. Hydrogen Gas
3. Mercury
4. Diamond

✅ Correct Answer: 2

The enthalpy of vaporisation of a substance is 8400 J mol-1 and its boiling point is –173°C. The entropy change for vaporisation is :

1. 84 J mol-1K-1
2. 21 J mol-1K-1
3. 49 J mol-1K-1
4. 12 J mol-1K-1

✅ Correct Answer: 1

The species which by definition has ZERO standard molar enthalpy of formation at 298 K is

1. Br2(g)
2. Cl2(g)
3. H2O(g)
4. CH4(g)

✅ Correct Answer: 2

In a reversible process the system absorbs 600 kJ heat and performs 250 kJ work on the surroundings. What is the increase in the internal energy of the system?

1. 850 kJ
2. 600 kJ
3. 350 kJ
4. 250 kJ

✅ Correct Answer: 3

Which of the following is true for the reaction? H2O (l) ↔ H2O (g) at 100° C and 1 atm pressure

1. ∆S = 0
2. ∆H = T ∆S
3. ∆H = ∆U
4. ∆H = 0

✅ Correct Answer: 1

Calculate the heat required to make 6.4 Kg CaC2 from CaO(s) and C(s) from the reaction: CaO(s) + 3 C(s) → CaC2(s) + CO (g) given that ∆f Ho (CaC2) = -14.2 kcal. ∆f H° (CO) = -26.4 kcal.

1. 5624 kcal
2. 1.11 × 104 kcal
3. 86.24 × 10³
4. 1100 kcal

✅ Correct Answer: 2

In a system where ∆E = -51.0 kJ, a piston expanded against a pext of 1.2 atm giving a change in volume of 32.0 L. What was the change in heat of this system?

1. -36 kJ
2. -13 kJ
3. -47 kJ
4. 24 kJ

✅ Correct Answer: 3

A system absorb 10 kJ of heat at constant volume and its temperature rises from 270 C to 370 C. The value of ∆ U is

1. 100 kJ
2. 10 kJ
3. 0 kJ
4. 1 kJ

✅ Correct Answer: 2

An ideal gas is taken around the cycle ABCA as shown in P-V diagram The next work done by the gas during the cycle is equal to:

1. 12P1V1
2. 6P1V1
3. 5P1V1
4. P1V1

✅ Correct Answer: 3

In which of the following process, a maximum increase in entropy is observed?

1. Dissolution of Salt in Water
2. Condensation of Water
3. Sublimation of Naphthalene
4. Melting of Ice

✅ Correct Answer: 3

The bond energy (in kcal mol-1) of a C-C single bond is approximately

1. 1
2. 10
3. 83-85
4. 1000

✅ Correct Answer: 3

Which thermodynamic function accounts automatically for enthalpy and entropy both?

1. Helmholtz Free Energy (A)
2. Internal Energy (E)
3. Work Function
4. Gibbs Free Energy

✅ Correct Answer: 4

The enthalpies of combustion of carbon and carbon monoxide are -393.5 and -283.0 kJ mol-1 respectively. The enthalpy of formation of carbon monoxide is:

1. -676 kJ
2. 110.5 kJ
3. -110.5 kJ
4. 676.5 kJ

✅ Correct Answer: 3

The amount of the heat released when 20 ml 0.5 M NaOH is mixed with 100 ml 0.1 M HCl is x kJ. The heat of neutralization is

1. -100 × kJ/mol
2. -50 × kJ/mol
3. 100 × KJ/mol
4. 50 × kJ/mol

✅ Correct Answer: 1

Based on the first law of thermodynamics, which one of the following is correct?

1. For an isothermal process, q = +w
2. For an isochoric process, ΔU = -q
3. For an adiabatic process, ΔU = -w
4. For a cyclic process, q = -w

✅ Correct Answer: 4

The temperature of the system decreases in an ______.

1. Adiabatic Compression
2. Isothermal Expansion
3. Isothermal Compression
4. Adiabatic Expansion

✅ Correct Answer: 4

Which of the following salts will have maximum cooling effect when 0.5 mole of the salt is dissolved in same amount of water. Integral heat of solution at 298 K is given for each salt?

1. KNO3 (∆H = 35.4 kJ mol-1)
2. NaCl (∆H = 5.35 kJ mol-1)
3. HBr (∆H = -83.3 kJ mol-1)
4. KOH ( ∆H = -55.6 kJ mol-1)

✅ Correct Answer: 1

Standard enthalpy of vapourisation ΔHvap for water at 100oC is 40.66 kJmol-1. The internal energy of vapourisation of water at 100°C (in kJmol-1) is (Assume water vapour to behave like an ideal gas)

1. 43.76
2. 40.66
3. 37.56
4. -43.76

✅ Correct Answer: 3

The solubility of Ca3(PO4)2 in water is y mol/L. Its solubility product is:

1. 6y²
2. 36 y4
3. 64 y5
4. 108 y5

✅ Correct Answer: 4

A physician wishes to prepare a buffer solution at pH = 3.85 that efficiently resists changes in pH yet contains only small concentration of the buffering agents. Which of the following weak acids together with its sodium salt would be best to use?

1. 2, 5-Dihydroxy benzoic acid (pKa = 2.97)
2. Acetoacetic acid (pKa = 3.58)
3. m-Chlorobenzoic acid (pKa = 3.98)
4. p-Chlorocinnamic acid (pKa = 4.41)

✅ Correct Answer: 2

What is the pH of a 0.10 M solution of barium hydroxide, Ba (OH)2?

1. 11.31
2. 11.7
3. 13.30
4. None of these

✅ Correct Answer: 3

Which of the following oxides is not expected to react with sodium hydroxide?

1. CaO
2. SiO2
3. BeO
4. B2O3

✅ Correct Answer: 1

The pH of a 10-10 M NaOH solution is nearest to

1. 10
2. 7
3. 4
4. -10

✅ Correct Answer: 3

A weak acid HX has the dissociation constant 1 × 10-5 M. It forms a salt NaX on reaction with alkali. The degree of hydrolysis of 0.1 M solution of NaX is

1. 0.0001%
2. 0.01%
3. 0.1%
4. 0.15%

✅ Correct Answer: 2

When equal volumes of 0.1 M NaOH and 0.01 M HCl are mixed, the hydroxide ion concentration is

1. 7.0
2. 1.04
3. 12.65
4. 2.0

✅ Correct Answer: 3

Concentration of the Ag+ ions in a saturated solution of Ag2C2O4 is 2.2 x 10-4 mol L-1. Solubility product of Ag2C2O42 is

1. 2.66 × 10-12
2. 4.5 × 10-11
3. 5.3 × 10-12
4. 2.42 × 10-8

✅ Correct Answer: 3

In a reversible chemical reaction at equilibrium, if the concentration of any one of the reactants is doubled, then the equilibrium constant will

1. Also be Doubled
2. Be Halved
3. Remain the Same
4. Become One-Fourth

✅ Correct Answer: 3

When a neutral atom undergoes oxidation, the atoms oxidation state

1. Decreases as it gains electrons
2. Decreases as it loses electrons
3. Increases as it gains electrons
4. Increases as it loses electrons

✅ Correct Answer: 4

Concentration of the Ag-4 ions in a saturated solution of Ag2C2O4 is 2.2 × (a) 10-4 mol L-1. Solubility product of Ag2C2O4 is

1. 2.66 × 10-12
2. 2.42 × 10-8
3. 4.5 × 10-11
4. 5.3 × 10-12

✅ Correct Answer: 3

Among the following the weakest Bronsted base is

1. F–
2. Cl–
3. Br–
4. I–

✅ Correct Answer: 4

A certain buffer solution contains equal concentration of X– and HX. The ka for HX is 10-8. The pH of the buffer is

1. 3
2. 8
3. 11
4. 14

✅ Correct Answer: 2

Solubility of M2S salt is 3.5 × 10-6 then find out solubility product.

1. 1.7 × 10-6
2. 1.7 × 10-16
3. 1.7 × 10-18
4. 1.7 × 10-12

✅ Correct Answer: 2

Among the following hydroxides, the one which has the lowest value of Ksp at ordinary temperature (about 25°C ) is

1. Mg (OH)2
2. Ca(OH)2
3. Ba(OH)2
4. Be(OH)2

✅ Correct Answer: 4

Which of the following mixtures in aqueous solution of equimolar concentration acts as a buffer solution?

1. HNO3 and NaOH
2. H2SO4 and KOH
3. NH4OH(excess) + HCl
4. CH3COOH and NaOH(excess)

✅ Correct Answer: 3

Amines behave as

1. Lewis Acids
2. Lewis Base
3. Aprotic Acid
4. Neutral Compound

✅ Correct Answer: 2

The oxidation number of Cl in Cl2O7 is

1. + 7
2. + 5
3. + 3
4. – 7

✅ Correct Answer: 1

What is known as Autooxidation?

1. ormation of H2O by the oxidation of H2O2.
2. Formation of H2O2 by the oxidation of H2O
3. Both (1) and (2) are true
4. None of the above

✅ Correct Answer: 2

The tendency of an electrode to lose electrons is known as

1. Electrode Potential
2. Reduction Potential
3. Oxidation Potential
4. E.M.F.

✅ Correct Answer: 3

If equal volumes of 1M KMnO4 and 1M K2Cr2O7 solutions are allowed to oxidize Fe2+ in acidic medium. The amount of iron oxidized will be:

1. More with KMnO2
2. More with K2Cr2O7
3. Equal with both oxidising agents
4. Cannot be determined

✅ Correct Answer: 2

Which of the following processes does not involve either oxidation or reduction?

1. Formation of slaked lime from quick lime
2. Heating Mercuric Oxide
3. Formation of Manganese Chloride from Manganese oxide
4. Formation of Zinc from Zinc blende

✅ Correct Answer: 1

One mole of N2H4 loses ten moles of electrons to form a new compound A. Assuming that all the nitrogen appears in the new compound, what is the oxidation state of nitrogen in A? (There is no change in the oxidation state of hydrogen.)

1. -1
2. -3
3. +3
4. +5

✅ Correct Answer: 3

How many millilitres of 0.5 M H2SO4 are needed to dissolve 0.5 g of copper(II)carbonate?

1. 6.01
2. 4.5
3. 8.1
4. 11.1

✅ Correct Answer: 3

The oxidation state of Cr in Cr (CO)6 is

1. 0
2. 2
3. 4
4. 6

✅ Correct Answer: 1

Which of the following processes does not involve oxidation of iron?

1. Formation of Fe(CO)5 from Fe.
2. Liberation of H2 from steam by iron at high temperature.
3. Rusting of iron sheets.
4. Decolourisation of blue CuSO4 solution by iron.

✅ Correct Answer: 1

The number of moles of KMnO4 reduced by one mole of KI in alkaline medium is

1. One
2. Two
3. Five
4. One fifth.

✅ Correct Answer: 2

Which of the following reactions does not involve either oxidation or reduction?

1. VO2+ → V2O3
2. Na → Na+
3. CrO2-4 → Cr2O2-7
4. Zn2+ →Zn

✅ Correct Answer: 3

KMnO4 reacts with oxalic acid according to the equation 2MnO4– + 5C2O42- + 16H+ → 2Mn2+ +10CO2 + 8H2O Here 20 mL of 0.1 M KMnO4 is equivalent to

1. 50 mL of 0.5 M C2H2O4
2. 20 mL of 0.1 M C2H2O4
3. 20 mL of 0.5 M C2H2O4
4. 50 mL of 0.1 M C2H2O4

✅ Correct Answer: 4

What is n-factor?

1. Equal to product of Number of moles of electrons when Lost or gained by one mole of reductant or oxidant
2. When Number of moles of electrons Lost or gained by one mole of reductant or oxidant is not same.
3. Equal to Number of moles of electrons Lost or gained by one mole of reductant or oxidant
4. None of the above

✅ Correct Answer: 3

The oxidation number of Mn is maximum in

1. MnO2
2. K2MnO4
3. Mn3O4
4. KMnO4

✅ Correct Answer: 4

The oxidation process involves

1. Increase in oxidation number
2. Decrease in oxidation number
3. No change in oxidation number
4. None of the above

✅ Correct Answer: 1

Metals generally react with dilute acids to produce hydrogen gas. Which one of the following metals does not react with dilute hydrochloric acid?

1. Copper
2. Magnesium
3. Iron
4. Silver

✅ Correct Answer: 2

The oxidation number of Xe in BaXeO6 is

1. 8
2. 6
3. 4
4. 10

✅ Correct Answer: 4

The colourless solution of silver nitrate slowly turns blue on adding copper chips to it because of

1. Dissolution of Copper
2. Oxidation of Ag+ → Ag
3. Reduction of Cu2+ ions
4. Oxidation of Cu atoms.

✅ Correct Answer: 4

A standard reduction electrode potentials of four metals are A = -0.250 V, B = -0.140 V, C = -0.126 V, D = -0.402 V The metal that displaces A from its aqueous solution is:

1. A
2. B
3. C
4. D

✅ Correct Answer: 4

Pure H2O2 is :

1. Semi – solid
2. Liquid
3. Solid
4. Gas

✅ Correct Answer: 2

The freezing point of heavy water is

1. 0°C
2. 3.8°C
3. 4°C
4. 1°C

✅ Correct Answer: 2

H2O2 used in rocket has the concentration:

1. 50%
2. 90%
3. 70%
4. 30%

✅ Correct Answer: 2

Which of the following hydrides are generally nonstochiometric in nature?

1. Ionic Hydrides
2. Molecular Hydrides
3. Interstitial Hydrides
4. All of the Above.

✅ Correct Answer: 3

What is the product of the reaction of H2O2 with Cl2?

1. O2 + HOCl
2. HCl + O2
3. H2O + HCl
4. HCl + H2

✅ Correct Answer: 2

Water shows anomalous behavior between

1. 0 to 4°C
2. 0 to 5°C
3. 0 to -4°C
4. 4 to 0°C

✅ Correct Answer: 1

Which of the following statements regarding hydrogen peroxide is/ are incorrect?

1. As aerating agent in production of sponge rubber
2. As an antichlor
3. For restoring white colour of blackened lead painting
4. All of the above

✅ Correct Answer: 4

Atomic hydrogen is called

1. Protium
2. Deutrium
3. Nascent Hydrogen
4. Tritium

✅ Correct Answer: 3

The volume strength of 1.5 NH2O2 solution is :

1. 4.8
2. 5.2
3. 8.8
4. 8.4

✅ Correct Answer: 4

Water gas is mixture of hydrogen H2 and

1. CO
2. CO2
3. Cl2
4. SO2

✅ Correct Answer: 1

Hydrogen has isotopes

1. 2
2. 3
3. 4
4. 5

✅ Correct Answer: 3

Pure H2O2 is:

1. Semi – solid
2. Liquid
3. Solid
4. Gas

✅ Correct Answer: 2

_________________ on water decolourises H2O2

1. O3
2. Acidic KMnO4 solution
3. Black Suspension of Lead Sulphide(PbS)
4. None of these

✅ Correct Answer: 3

What is gram equivalent weight of hydrogen peroxide as reductant?

1. 100
2. 125
3. 152
4. None of the above

✅ Correct Answer: 3

Hydrogen is the most abundant element on earth after______.

1. Oxygen
2. Carbon
3. Sulphur
4. None of the above

✅ Correct Answer: 1

Hydrogen is a good __________ agent.

1. Oxidizing
2. Reducing
3. Acidic
4. Basic

✅ Correct Answer: 2

The volume of 10 volume H2O2 required to liberate 500 ml of O2 at S.T.P. is :

1. 25 ml
2. 50 ml
3. 100 ml
4. 125 ml

✅ Correct Answer: 2

Hydrogen is most __________ element in the universe.

1. Abundant
2. None
3. Both
4. Consumer

✅ Correct Answer: 1

CsOH is

1. Strongly basic
2. Weakly basic
3. Slightly acidic
4. Amphoteric.

✅ Correct Answer: 1

Alkali metals give a _________________when dissolved in liquid ammonia

1. Deep blue solution
2. Colourless
3. Red colour
4. None of the above

✅ Correct Answer: 1

What are Oxo-Acids?

1. Acid containing Oxygen
2. Acid containing Sulphur
3. Acid containing Carbon
4. None of the above

✅ Correct Answer: 1

In curing cement plasters, water is sprinkled from time to time. This helps in

1. Converting sand into silicic acid
2. Keeping it cool
3. Developing interlocking needle like crystals of hydrated silicates
4. Hydrating sand and gravel mixed with cement.

✅ Correct Answer: 3

The substance not likely to contain CaCO3 is

1. Dolomite
2. A marble statue
3. Calcined gypsum
4. Sea shells

✅ Correct Answer: 3

Carnallite is the mineral of:

1. Na
2. Ca
3. Mg
4. None of the above

✅ Correct Answer: 3

The wire of flash bulb is made up of:

1. Mg
2. Ag
3. Cu
4. Ba

✅ Correct Answer: 1

The basic strength of which hydroxide is maximum

1. LiOH
2. NaOH
3. Ca (OH)2
4. KOH

✅ Correct Answer: 4

The composition of Sorels cement is

1. KCl × MgCl2× 6H2O
2. MgCl2 × 5MgO × (xH2O)
3. MgCO3 × CaCO3
4. CaSO4 × 2H2O

✅ Correct Answer: 2

Which of the following alkali metals has the least melting point?

1. Na
2. K
3. Rb
4. Cs

✅ Correct Answer: 4

The hydration energy of Mg2+ is larger than that of

1. A13+
2. Na+
3. Be26
4. Mg3+

✅ Correct Answer: 2

Milk of lime reacts with chlorine to form ________, a constituent of bleaching powder.

1. Ca(OCI)2
2. Ca(CIO2)2
3. Ca(CIO3)2
4. Ca(CIO4)2

✅ Correct Answer: 1