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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Related Posts:
- Focus guide for 11th Chemistry and Physics PDF free download in English Medium Volume 1 and Volume 2
- 11th Chemistry Guide in Tamil Medium
- Kendriya Vidyalaya Question Papers Class 11 Chemistry
Focus Chemistry Guide for 11th Objective for Students
In DNA, which type of bond links successive deoxynucleotides?
a. Phosphomonoester bond
b. Phosphodiester bond
c. Phosphotriester bond
d. Amide bond
Option b – Phosphodiester bond
Which compound does not show mutarotation?
a. Sucrose
b. Lactose
c. Maltose
d. Fructose
Option a – Sucrose
Which section of DNA provides instructions for protein synthesis?
a. Nucleotide
b. Ribose
c. Gene
d. Nucleoside
Option c – Gene
What gives RNA and DNA their chiral nature?
a. L-form sugar units
b. Chiral nitrogenous bases
c. Chiral phosphate esters
d. D-form sugar units
Option d – D-form sugar units
How many ATP molecules are used to produce one glucose molecule during photosynthesis?
a. 6
b. 8
c. 10
d. 18
Option d – 18
Which of the following is absent in DNA structure?
a. Thymine
b. Quinoline
c. Adenine
d. Cytosine
Option b – Quinoline
A straight-chain tetrapeptide made of different amino acids has how many amino acids and peptide bonds?
a. 4 and 4
b. 5 and 5
c. 5 and 4
d. 4 and 3
Option d – 4 and 3
Which noble gas is commonly used in nuclear reactors?
a. Krypton
b. Oxygen
c. Neon
d. Helium
Option d – Helium
Identify the correct statement regarding phosphinic and phosphonic acids:
a. Phosphinic acid donates one proton, phosphonic acid donates two
b. Phosphinic acid donates two protons, phosphonic acid donates one
c. Both are triprotic acids
d. Both are diprotic acids
Choose the correct order of acid strength:
a. HClO < HClO₂ < HClO₃ < HClO₄
b. HClO₂ < HClO < HClO₃ < HClO₄
c. HClO₄ < HClO₂ < HClO < HClO₃
d. HClO₃ < HClO₄ < HClO₂ < HClO
Option a – HClO < HClO₂ < HClO₃ < HClO₄
How many lone electron pairs are on chlorine in ClF₃?
a. Four
b. Two
c. One
d. Three
Option b – Two
Which molecule has a bond angle of exactly 120°?
a. PH₃
b. ClF₃
c. NCl₃
d. BCl₃
Option d – BCl₃
When XeF₆ reacts with a strong base, what is the oxidation number of xenon in the resulting compound?
a. +2
b. +4
c. +6
d. +8
Option d – +8
What gas is commonly used in inflating airplane tires? ( Focus Chemistry Guide for 11th QnA )
a. Hydrogen
b. Helium
c. Nitrogen
d. Argon
Option b – Helium
Which statement is incorrect about halogens?
a. All except fluorine exhibit positive oxidation states
b. All act as oxidizing agents
c. Each forms monobasic oxyacids
d. Chlorine has the highest electron affinity
Option a – All except fluorine exhibit positive oxidation states
Which of the following molecules is non-existent? ( Focus Chemistry Guide for 11th QnA )
a. O₂
b. He₂
c. Li₂
d. C₂
Option b – He₂
What is the correct order of thermal stability among H₂E (E = O, S, Se, Te, 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 < H₂Te < H₂Se < H₂S < H₂O
Which of the following is not categorized as a greenhouse gas?
a. Methane
b. Ozone
c. Sulfur dioxide
d. Nitrous oxide
Option c – Sulfur dioxide
How are hydrates of noble gases like argon, krypton, and xenon typically formed?
a. Covalent bonding
b. Charge transfer
c. Ionic bonding
d. By trapping gas atoms in ice cavities
Option d – By trapping gas atoms in ice cavities
Which xenon fluoride compound does not exist? ( Focus Chemistry Guide for 11th QnA )
a. XeF₆
b. XeF₄
c. XeF₃
d. XeF₂
Option d – XeF₂
What is the geometry of the XeF₂ molecule?
a. Square planar
b. Trigonal bipyramidal
c. Trigonal planar
d. Linear
Option d – Linear
Which xenon compounds have the same number of lone pairs on the xenon atom?
a. XeO₃ and XeOF₄ only
b. XeO₃ and XeF₆ only
c. XeOF₄ and XeF₆ only
d. XeO₃, XeOF₄, and XeF₆
Option d – XeO₃, XeOF₄, and XeF₆
What is the shape of XeO₃? ( Focus Chemistry Guide for 11th QnA )
a. Linear
b. Planar
c. Pyramidal
d. T-shaped
Option c – Pyramidal
Which xenon fluoride compound has zero dipole moment?
a. XeF₆
b. XeO₃
c. XeF₄
d. XeF₂
Option c – XeF₄
What is the molecular nature of inert gases?
a. Polyatomic
b. Triatomic
c. Diatomic
d. Monoatomic
Option d – Monoatomic
What gas combination is used by deep sea divers for respiration? ( Focus Chemistry Guide for 11th QnA )
a. Oxygen and argon
b. Oxygen and helium
c. Oxygen and nitrogen
d. Oxygen and hydrogen
Option b – Oxygen and helium
Which gas mixture is commonly used to assist asthma patients?
a. Helium and oxygen
b. Neon and oxygen
c. Xenon and nitrogen
d. Argon and oxygen
Option a – Helium and oxygen
The term noble gas refers to which group of elements?
(A) 13 group
(B) 14 group
(C) 18 group
(D) 12 group
Option c – 18 group
The ease of liquefaction of noble gases follows 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 noble gas has the highest polarizability? ( Focus Chemistry Guide for 11th QnA )
(A) He
(B) Kr
(C) Xe
(D) Ar
Option c – Xe
What is the electron affinity of noble gases?
(A) Low
(B) High
(C) Zero
(D) Negative
Option c – Zero
Which statement about SO₂ is incorrect?
(A) It acts as a 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? ( Focus Chemistry Guide for 11th QnA )
(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 compound is sulphur in the +5 oxidation state?
(A) Dithionic acid
(B) Sulphurous acid
(C) Sulphuric acid
(D) Disulphuric acid
Option a – Dithionic acid
Why is SO₃ not directly dissolved in water to form sulphuric acid?
(A) SO₃ does not react with water to form acid
(B) SO₃ gets oxidised to H₂SO₃ in water
(C) A dense fog of sulphuric acid forms, which is hard to condense
(D) SO₃ is insoluble in water due to its covalent nature
Option c – A dense fog of sulphuric acid forms, which is hard to condense
What is the nature of sulphuric acid dissolution in water? ( Focus Chemistry Guide for 11th QnA )
(A) Endothermic
(B) Exothermic
(C) Dehydrating
(D) Displacement
Option b – Exothermic
Why can’t the covalency of oxygen exceed 2 like sulphur?
(A) Oxygen atom lacks d-orbitals
(B) Oxygen has only two unpaired electrons
(C) Oxygen forms double bonds with another oxygen atom
(D) Small size prevents electron promotion to d-orbitals
Option a – Oxygen atom lacks d-orbitals
Which of the following is not correctly matched?
(A) Acidic oxides – P₂O₅, NO₂, Cl₂O₇
(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 an air pollutant?
(A) It increases atmospheric temperature
(B) It is an insecticide
(C) It causes acid rain by forming sulphuric acid with O₂ and H₂O
(D) It is a strong oxidising agent
Option c – It causes acid rain by forming sulphuric acid with O₂ and H₂O
What effect do enzymes have on the rate of biochemical reactions? ( Focus Chemistry Guide for 11th QnA )
(A) Increases
(B) Decreases
(C) Remains the same
(D) No effect
Option a – Increases
For a first-order reaction, if reducing concentration to 1/4 takes 20 min, how long to reach 1/16?
(A) 20 min
(B) 80 min
(C) 10 min
(D) 40 min
Option d – 40 min
In a zero-order reaction, the rate doubles for every 10°C rise. Going from 10°C to 100°C, the rate becomes
(A) 256 times
(B) 512 times
(C) 64 times
(D) 128 times
Option b – 512 times
What is the key concept of the absolute reaction rate theory? ( Focus Chemistry Guide for 11th QnA )
(A) Formation of activated complex
(B) Reactant collisions
(C) Matching potential energy
(D) Decrease in entropy
Option a – Formation of activated complex
If doubling reactant halves the half-life, the reaction order is
(A) 0.5
(B) 1
(C) 2
(D) 0
Option c – 2
What is the temperature coefficient of a reaction?
(A) Reaction rate at 25°C
(B) Reaction rate at 100°C
(C) Ratio of rate constants at 35°C and 25°C
(D) Ratio of rate constants with 1°C difference
Option c – Ratio of rate constants at 35°C and 25°C
If initial reactant concentration doesn’t affect half-life, the reaction order is
(A) Zero
(B) First
(C) Second
(D) Between zero and first
Option b – First
Which of the following is incorrect? ( Focus Chemistry Guide for 11th QnA )
(A) Catalysts do not initiate reactions
(B) Catalysts change equilibrium constant
(C) Enzymes catalyze biochemical reactions
(D) Coenzymes boost enzyme activity
Option b – Catalysts change equilibrium constant
PH₃ decomposes on tungsten as a first-order reaction because
(A) Rate ∝ surface coverage
(B) Rate ∝ 1/surface coverage
(C) Rate is independent of coverage
(D) Decomposition rate is slow
Option a – Rate ∝ surface coverage
The units of Arrhenius constant are equal to
(A) Rate constant
(B) Activation energy
(C) Threshold energy
(D) Probability factor
Option a – Rate constant
For a first-order reaction, time for 99% completion is
(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: ( Focus Chemistry Guide for 11th QnA )
(1) Corrosion can be minimized by contact with a metal of higher reduction potential
(2) Iron corrodes in oxygen-free water
(3) Corrosion can be minimized by an impermeable barrier
(4) Iron corrodes faster in saltwater
Option c – Corrosion can be minimized by an impermeable barrier
In the cell Zn | ZnSO₄ (0.01 M) || CuSO₄ (1.0 M) | Cu, if ZnSO₄ becomes 1.0 M and CuSO₄ becomes 0.01 M, then
(A) E₁ < E₂
(B) E₁ > E₂
(C) E₂ = 0.5 E₁
(D) E₁ = E₂
Option b – E₁ > E₂
Galvanization involves coating iron with
(1) Pb
(2) Cr
(3) Cu
(4) Zn
Option b – Cr
Passing 2 Faradays through CuSO₄ deposits how much copper? (Atomic mass of Cu = 63.5)
(1) 2 g
(2) 124 g
(3) 0 g
(4) 63.5 g
Option d – 63.5 g
Oxidation of succinate yields gases. Passing 0.2 Faraday gives what volume at STP? ( Focus Chemistry Guide for 11th QnA )
(1) 8.96 L
(2) 4.48 L
(3) 6.72 L
(4) 2.24 L
Option a – 8.96 L
In a galvanic cell, the salt bridge
(1) Does not participate in the reaction
(2) Stops ion diffusion
(3) Is essential for reaction
(4) Mixes electrolytic solutions
Option b – Stops ion diffusion
For a hydrogen electrode in pH = 10 HCl, oxidation potential is
(A) 0.059 V
(B) 0.59 V
(C) 0.118 V
(D) 1.18 V
Option c – 0.118 V
Why is Zn used to galvanize iron, but not vice versa? ( Focus Chemistry Guide for 11th QnA )
(A) Zn is lighter
(B) Zn melts more easily
(C) Zn has lower negative potential
(D) Zn has higher negative potential
Option d – Zn has higher negative potential
A device converting combustion energy to electricity is a
(A) Fuel cell
(B) Electrolytic cell
(C) Dynamo
(D) Ni-Cd cell
Option c – Dynamo
Best conductor of electric current among these? ( Focus Chemistry Guide for 11th QnA )
(A) Acetic acid
(B) Hydrochloric acid
(C) Ammonia
(D) Fructose
Option b – Hydrochloric acid
Electrode potentials of X, Y, Z are -1.2 V, +0.5 V, -3.0 V. Reducing power?
(A) Y > X > Z
(B) Z > X > Y
(C) X > Y > Z
(D) Y > Z > X
Option b – Z > X > Y
Hydrogen electrode with pH = 10 HCl gives oxidation potential
(A) 0.59 V
(B) 0.118 V
(C) 1.18 V
(D) 0.059 V
Option a – 0.59 V
We covered all the focus chemistry guide for 11th mcqs above in this post for free so that you can practice well for the exam.
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Also, check out:
- Introduction to Analytical Chemistry Class 11
- Companion Chemistry Class 11
- Sura Guide 11th Chemistry
