Focus Chemistry Guide for 11th. We covered all the Focus Chemistry Guide for 11th MCQs in this post for free so that you can practice well for the exam.
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- 11th Chemistry Guide in Tamil Medium
- Kendriya Vidyalaya Question Papers Class 11 Chemistry
Focus Chemistry Guide for 11th Objective for Students
In DNA, the consecutive deoxynucleotides are connected via
(A) Phosphomonoester linkage
(B) Phosphodiester linkage
(C) Phosphotriester linkage
(D) Amid linkage
Option b – Phosphodiester linkage
Which of the following does not exhibit the phenomenon of mutarotation?
(A) (+) Sucrose
(B) (+) Lactose
(C) (+) Maltose
(D) (-) Fructose
Option a – (+) Sucrose
The segment of DNA that acts as the instructional manual for the synthesis of proteins is
(A) Nucleotide
(B) Ribose
(C) Gene
(D) Nucleoside
Option c – Gene
RNA and DNA are chiral molecules, and their chirality is due to
(A) L-sugar component
(B) Chiral bases
(C) Chiral phosphate ester units
(D) D-sugar component
Option d – D-sugar component
Synthesis of each molecule of glucose in photosynthesis involves
(A) 6 molecules of ATP
(B) 8 molecules of ATP
(C) 10 molecules of ATP
(D) 18 molecules of ATP
Option d – 18 molecules of ATP
Which one of the following bases is not present in DNA?
(A) Thymine
(B) Quinoline
(C) Adenine
(D) Cytosine
Option b – Quinoline
The number of amino acids and the number of peptide bonds in a linear tetrapeptide (made of different amino acids) are respectively
(A) 4 and 4
(B) 5 and 5
(C) 5 and 4
(D) 4 and 3
Option d – 4 and 3
The noble gas used in a nuclear reactor is
(A) Krypton
(B) Oxygen
(C) Neon
(D) Helium
Option d – Helium
Which is the correct statement for the given acids?
(A) Phosphinic acid is a monoprotic acid while phosphonic acid is a diprotic acid
(B) Phosphinic acid is a diprotic acid while phosphonic acid is a monoprotic acid
(C) Both are triprotic acids.
(D) Both are diprotic acids.
Option a – Phosphinic acid is a monoprotic acid while phosphonic acid is a diprotic acid
Among the following, the correct order of acidity is
(A) HCIO < HCIO₂ < HCIO3 < HClO4
(B) HCIO₂<HCIO < HCIO3 < HCl04
(C) HCIO4 < HCIO₂ < HCIO < HCIO3
(D) HCIO3 < HCIO4 < HCIO₂ < HCIO
Option a – HCIO
In the structure of CIF3, the number of lone pairs of electrons on the central atom ‘Cl’ is
(A) Four
(B) Two
(C) One
(D) Three
Option b – Two
The species, having bond angles of 120° is
(A) PH3
(B) CIF3
(C) NCl3
(D) BCl3
Option d – BCl3
Xenon hexafluoride reacts with strong alkali to form a xenon compound X. The oxidation state of Xe in X is
(A) +2
(B) +4
(C) +6
(D) +8
Option d – +8
The gas used for inflating the types of airplanes is
(A) H₂
(B) He
(C) N₂
(D) Ar
Option b – He
Which of the following statements is not true for halogen?
(A) All but fluorine show positive oxidation.
(B) All are oxidizing agents.
(C) All form monobasic oxyacids.
(D) Chlorine has the highest electron-gain enthalpy
Option a – All but fluorine show positive oxidation
Identify a molecule that does not exist.
(A) O₂
(B) He₂
(C) Li₂
(D) C₂
Option b – He₂
Which is the correct thermal stability order for H₂E (E = O, S, Se, Te, and Po)?
(A) H₂O <H₂S <H₂Se <H₂Te < H₂Po
(B) H₂Po <H₂Te <H₂Se <H₂S < H₂O
(C) H₂Se <H₂Te <H₂Po <H₂O < H₂S
(D) H₂S <H₂O < H₂Se <H₂Te < H₂Po
Option b – H₂Po
Among the following the one that is not a greenhouse gas is
(A) Methane
(B) Ozone
(C) Sulphur dioxide
(D) Nitrous oxide
Option c – Sulphur dioxide
How are noble gas hydrates of argon, krypton, and xenon formed?
(A) Covalent bond
(B) Charged transfer
(C) Ionic bond
(D) Trapping noble gas atoms in the cavities of frozen water
Option d – Trapping noble gas atoms in the cavities of frozen water
Which of the following fluorides of xenon is impossible?
(A) XeF6
(B) XeF4
(C) XeF3
(D) XeF2
Option d – XeF2
XeF2 Molecule is
(A) Square planer
(B) Trigonal bipyramidal
(C) Trigonal planer
(D) Linear
Option d – Linear
Among the following molecule (i) XeO3 (ii) XeOF4 (iii) XeF6 Those having the same number of lone pairs on Xe are
(A) (i) and (ii) only
(B) (i) and (iii) only
(C) (ii) and (iii) only
(D) (i), (ii), and (iii)
Option d – (i), (ii), and (iii)
The structure of XeO3 is
(A) Linear
(B) Planar
(C) Pyramidal
(D) T-Shaped
Option c – Pyramidal
The fluoride of xenon with zero dipole moment
(A) XeF6
(B) XeO3
(C) XeF4
(D) XeF2
Option c – XeF4
The inert gases are
(A) Polyatomic
(B) Triatomic
(C) Diatomic
(D) Monoatomic
Option d – Monoatomic
Deep sea divers used to respire is a mixture of
(A) Oxygen and argon
(B) Oxygen and helium
(C) Oxygen and nitrogen
(D) Oxygen and hydrogen
Option b – Oxygen and helium
Which of the following is the life-saving mixture for an asthma patient?
(A) A mixture of helium and oxygen.
(B) A mixture of neon and oxygen.
(C) A mixture of xenon and nitrogen
(D) Mixture of argon and oxygen
Option a – A mixture of helium and oxygen
The term noble gas is referred to which group of elements?
(A) 13 group
(B) 14 group
(C) 18 group
(D) 12 group
Option c – 18 group
The ease of liquefication of noble gas decreases in the order
(A) He> Ne> Ar> Kr> Xe
(B) Xe > Kr> Ar> Ne > He
(C) Ar > Kr> Xe > He > Ne
(D) Kr> Xe > He > Ar> Ne
Option b – Xe > Kr> Ar> Ne > He
Which of the noble gas has the highest polarizability?
(A) He
(B) Kr
(C) Xe
(D) Ar
Option c – Xe
The electron affinity of noble gas is
(A) Low
(B) High
(C) Zero
(D) Negative
Option c – Zero
Which of the following statements is not correct for SO₂ gas?
(A) It acts bleaching agent in moist conditions.
(B) Its dilute solution is used as a disinfectant.
(C) Its molecules have linear geometry.
(D) Acidified KMnO4 is decolourised when SO₂ is passed through it.
Option c – Its molecules have linear geometry
Which of the following statements is not correct?
(A) The oxygen molecule is paramagnetic with two unpaired electrons.
(B) Sulphur shows maximum covalency of four.
(C) Ozone can be easily detected by mercury.
(D) Both sulphurous and sulphuric acid are dibasic in nature.
Option b – Sulphur shows maximum covalency of four
In which of the following sulphur is present in the +5 oxidation state?
(A) Dithionic acid
(B) Sulphurous acid
(C) Sulphuric acid
(D) Disulphuric acid
Option a – Dithionic acid
Sulphur trioxide is not directly dissolved in water to form sulphuric acid because
(A) SO3 does not react with water to form acid
(B) SO3 gets oxidised to H₂SO3 when dissolved in water.
(C) It results in the formation of a dense fog of sulphuric acid which is difficult to condense.
(D) Sulphur trioxide is insoluble in water due to its covalent nature.
Option c – It results in the formation of a dense fog of sulphuric acid which is difficult to condense
The dissolution of sulphuric acid in water is
(A) An endothermic process
(B) An exothermic process
(C) A dehydrating process
(D) A displacement process
Option b – An exothermic process
The covalency of oxygen cannot exceed 2, unlike sulphur which can show +4 or +6 because
(A) Oxygen atom does not have d-orbitals.
(B) The oxygen atom has two unpaired electrons in its valance shell.
(C) Oxygen can form a double bond with another oxygen atom.
(D) Electrons of oxygen atoms cannot be promoted to d-orbitals due to their small size.
Option a – Oxygen atom does not have d-orbitals
Which of the following is not correctly matched?
(A) Acidic oxides – P2O5, NO2, Cl₂07
(B) Basic oxides – Na2O, CaO, MgO
(C) Neutral oxides – CO₂, CO, BeO
(D) Amphoteric oxides – ZnO, SnO, Al2O3
Option c – Neutral oxides – CO₂, CO, BeO
Why is sulphur dioxide considered as air pollution?
(A) It increases the temperature of the atmosphere.
(B) It is used as an insecticide which causes air pollution.
(C) causes acid rain due to the formation of sulphuric acid in combination with O₂ and H₂O.
(D) It is a strong oxidising agent and hence oxidises the other components of air.
Option c – causes acid rain due to the formation of sulphuric acid in combination with O₂ and H₂O
By the action of enzymes, the rate of biochemical reaction
(A) Increases
(B) Decreases
(C) Same
(D) Does not change
Option a – Increases
For a first-order reaction, the time taken to reduce the initial concentration by a factor of 1/4 is 20 min. The time required to reduce initial concentration by a factor of 1/16 is
(A) 20 min
(B) 80 min
(C) 10 min
(D) 40 min
Option d – 40 min
In a zero-order reaction, for every 10°C rise in temperature, the rate is doubled. If the temperature is increased from 10°C to 100°C, the rate of the reaction will become
(A) 256 times
(B) 512 times
(C) 64 times
(D) 128 times
Option b – 512 times
The salient feature of the theory of absolute reaction rates is the
(A) formation of the activated complex
(B) collision of the reactant molecules
(C) matching potential energy of the reactant molecules
(D) decrease of entropy of the reactant molecules
Option a – formation of the activated complex
The half-life of the reaction is halved as the initial concentration of the reactant is doubled. The order of the reaction is
(A) 0.5
(B) 1
(C) 2
(D) 0
Option c – 2
The temperature coefficient of a reaction is
(A) a Specific reaction with a rate of 25°C
(B) a Rate of the reaction at 100°C
(C) a Ratio of the rate constants at temperatures 35°C and 25°C.
(D) The ratio of the rate constants temperatures differing by 1°C.
Option c – a Ratio of the rate constants at temperatures 35°C and 25°C
When the initial concentration of a reactant is doubled in a reaction, its half-life period is not affected. The order of the reaction is
(A) Zero
(B) First
(C) Second
(D) More than zero but less than first
Option b – First
Which one of the following statements is not correct?
(A) Catalyst does not initiate any reaction
(B) The value of the equilibrium constant is changed in the presence of a catalyst in the reaction equilibrium
(C) Enzymes catalyze mainly biochemical reactions
(D) Coenzymes increase the catalytic activity of the enzyme
Option b – The value of the equilibrium constant is changed in the presence of a catalyst in the reaction equilibrium
The decomposition of phosphine (PH3) on tungsten at low pressure is a first-order reaction. It is because the
(A) Rate is proportional to the surface coverage
(B) Rate is inversely proportional to the surface coverage.
(C) Rate is independent of the surface coverage.
(D) Rate of decomposition is very slow.
Option a – Rate is proportional to the surface coverage
The units of the Arrhenius constant must be equal to
(A) Rate constant
(B) Activation of energy
(C) Threshold energy
(D) Probability factor
Option a – Rate constant
If the rate of constant for a first-order reaction is k, the time (t) required for the completion of 99% of the reaction is given by
(A) t = 6.909/k
(B) t = 4.606/k
(C) t = 2.303/k
(D) t = 0.693/k
Option b – t = 4.606/k
Identify the correct statement.
(1) Corrosion of iron can be minimized by forming contact with another metal with a higher reduction potential
(2) Iron corrodes in oxygen-free water.
(3) Corrosion of iron can be minimized by forming an impermeable barrier at its surface.
(4) Iron corrodes more rapidly in salt water because its electrochemical potential is higher
Option 3 – Corrosion of iron can be minimized by forming an impermeable barrier at its surface
In the electrochemical cell Zn | ZnSO4 (0.01 M) || CuSO4 (1.0 M) | Cu the emf of this Daniel cell is E₁. When the concentration of ZnSO4 is changed to 1.0 M and that of CuSO4 changed to 0.01 M, the emf changes to E₂ from the following which is the relationship between E₁ and E2?
(A) E₁ < E₂
(B) E₁ > E₂
(C) E₂ = 0’E₁
(D) E₁ = E₂
Option b – E₁ > E₂
Galvanization is applying a coating of
(1) Pb
(2) Cr
(3) Cu
(4) Zn
Option 2 – Cr
Two Faradays of electricity are passed through a solution of CuSO4. The mass of copper deposited at the cathose is (at, the mass of Cu 63.5 amu)
(1) 2 g
(2) 124 g
(3) Og
(4) 63.5 g
Option 4 – 63.5 g
Oxidation of succinate ions produces ethylene and carbon dioxide gases. On passing 0.2 Faraday electricity through an aqueous solution of potassium succinate, the total volume of gases (at both cathode and anode) at STP (1 atm and 273 K) is
(1) 8.96 L
(2) 4.48 L
(3) 6.72 L
(4) 2.24 L
Option 1 – 8.96 L
In a galvanic cell, the salt bridge
(1) does not participate chemically in the cell reaction
(2) stops the diffusion of ions from one electrode to another
(3) is necessary for the occurrence of the cell reaction
(4) ensures the mixing of the two electrolytic solutions.
Option 2 – stops the diffusion of ions from one electrode to another
A hydrogen gas electrode is made by dipping platinum wire in a solution of HCl of pH = 10 and by passing hydrogen gas around the platinum wire at 1 atm pressure. The oxidation potential of the electrode would be.
(A) 0.059 V
(B) 0.59 V
(C) 0.118 V
(D) 1.18 V
Option c – 0.118 V
Zinc can be coated on iron to produce galvanized iron but the reverse is not possible. It is because
(A) Zinc is lighter than iron
(B) Zinc has a lower melting point than iron
(C) Zinc has a lower negative electrode potential than iron
(D) Zinc has a higher negative electrode potential than iron
Option d – Zinc has a higher negative electrode potential than iron
A device that converts the energy of combustion of fuels like hydrogen and methane, directly into electrical energy is known as
(A) Fuel cell
(B) Electrolytic cell
(C) Dynamo
(D) Ni-Cd cell
Option c – Dynamo
An aqueous solution of which of the following compounds is the best conductor of electric current?
(A) Acetic acid, C₂H4O2
(B) Hydrochloric acid, HCl
(C) Ammonia, NH3
(D) Fructose, C5H12O6
Option b – Hydrochloric acid, HCl
The standard electrode potential of three metals X, Y, and Z are -12 V, + 0.5 V, and -3.0 V respectively. The reducing power of these metals will be
(A) Y> X> Z
(B) Z> X > Y
(C) X > Y > Z
(D) Y>Z> X
Option b – Z> X > Y
A hydrogen gas electrode is made by dipping platinum wire in a solution of HCl of (pH = 10) and by passing hydrogen gas around the platinum wire at one atm pressure. The oxidation potential of the electrode would be
(A) 0.59 volt
(B) 0.118 volt
(C) 1.18 volt
(D) 0.059 volt
Option a – 0.59 volt
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Also, check out:
- Introduction to Analytical Chemistry Class 11
- Companion Chemistry Class 11
- Sura Guide 11th Chemistry
