11th CBSE NCERT Chemistry Term 2 Examination 2021-22

11th CBSE NCERT Chemistry Mid Term Exam Set B Question Paper (2019-20)

Time: 3 Hrs.
Marks: 70
Class: 11th
Date: 13/09/2019

General Instructions:

1. All questions are compulsory (11th CBSE NCERT Chemistry Mid Term Exam).
2. Q’s 1 to 20 are of 1 mark each.
3. Q’s 21 to 27 are of 2 marks each.
4. Q’s 28 to 34 are of 4 marks each.
5. Q’s 35 to 37 are of 5 marks each.
6. All questions are compulsory.

Section A

Question: (i) In which one of the following pair the two species are isoelectronic

1. ³⁹K⁺ and ⁴⁰Ar
2. ²³Na and ²³Na⁺
3. ⁴⁰Ca²⁺ and 3⁹K
4. ²³Na and ²⁴Mg²⁺

Question: (ii). The no. of atoms in 0.1 ml of triatomic gas is

1. 1.800 × 10²²
2. 1.806 × 10²³
3. 6.026 × 10²²
4. 3.600 × 10²²

Question: (iii). Which of the following concentration term are dependent of temperature

1. Molality only
2. Molality and Mole fraction
3. Molarity and Normality
4. Molarity only

Question: (iv). The maximum no. of molecule is present in

1. 5l of N₂ gas at STP
2. 10 g of O₂ gas
3. 0.5 g of H₂ gas
4. 15 l of H₂ gas at STP

Question: (v) Which of the following sets of quantum numbers are not possible:

1. n = 3, l = 0, m = 0, S = +½
2. n = 3, l = 0, m = +10, S = -½
3. n = 3, l = 2, m = 0, S = -½

Question: (vi) The no. radial nodes of 3S and 2P Orbitals are

1. 2, 0
2. 0, 2
3. 1, 2
4. 2, 1

Question: (vii) The electron identified by quantum numbers n and l are:

1. n = 4, l = 1
2. n = 4, l = 0
3. n = 3, l = 2
4. n = 3, l = 1

Can be placed in order of increasing energy as

1. 4<2<3<1
2. 2<4<1<3
3. 1<3<2<4
4. 3<4<2<1

Question: (viii) Maximum no. of electrons in a shell with principal quantum n is given by:

1. n
2. 2n
3. n²
4. 2n²

Question: (ix) Which of the following trend is not correct for size

1. Na<K<Rb
2. I⁺ <I^–<I
3. Fe²+<Fe³+Fe
4. F<O<N

Question: (x) Which of the following properly increases along a period (in general)

1. Atomic size
2. Ionization enthalpy
3. electron gain enthalpy
4. Ionic size

Question: (xi). The highest negative electron gain enthalpy is of

1. N
2. O
3. S
4. Br

Question: (xii). The penetration of the electron in any principal shell varies as

1. s>p>d>f
2. s<p<d<f
3. s>p>d<f
4. s<p<d>f

Question: (xiii) Which of the following is the election deficient molecule

1. C₂H₆
2. B₂H₆
3. SiH₄
4. PH₂₃

Question: (xiv) In which of the following molecules, the central atom has two lone pair of electron

1. SF₄
2. BrF₅
3. SO₂
4. PH₂

Question: (xv) In which of following the bond angle between two covalent bonds is maximum?

1. H₂O
2. NH₃
3. CO₂
4. CH₄

Question: (xvi) The Hybridization of C involves in acetylene

1. SP²
2. SP³
3. SP
4. dSP²

Question: (xvii) What is the value of gas constant R in joules per degree per mole.

1. 1.987
2. 8.31 × 10⁷
3. 0.082
4. 8.314

Question: (xviii) The compressibility factor for an ideal gas is:

1. Unity at all temperature
2. Unity at Boyle’s temperature
3. Zero
4. decrease with pressure

Question: (xix) The term which accounts for intermolecular process is an Van Der Waal’s equation is:

1. V-b
2. (RT)^-1
3. (p + a/v²)
4. RT

Question: (xx) The ratio of partial pressure of gaseous component to the total vapour pressure of the mixture is equal to:

1. mass of the component
2. molefraction of the component
3. mass % of the component
4. molecular mass

Section B: 11th CBSE NCERT Chemistry Mid Term Exam

Question: (xxi)

1. State law of multiple proportion with suitable example.
2. What is limiting reagent.

Question: (xxii) Calculate the radius of Bohr’s 3^2rd Orbit in Li²⁺ ion.

Question: (xxiii) Write two difference between electronegativity and electron gain enthalpy.

Question: (xxiv) Define Octet rule. Write its limitation.

OR

Draw the Lewis dot symbol of the following molecule, atoms and ions.

1. CO₃^2-
2. O₃

Question: (xxv) Calculate the temperature of 4.0 moles of a gas occupying 5dm³ at 3.32 bar.

OR

Explain the physical significance of Van Der Wall Parameters.

Question: (xxvi) An element with mas number 81 contains 31.7% more neutrons as compared to proton assign the atomic symbol.

Question: (xxvii)

1. Why noble gas have the largest positive electron gain enthalpy in their respective periods.
2. Explain why chlorine can be converted into chloride ion more easily as compared to fluoride ion.

Section C

Question: (xxviii)

1. From the elements: Cl, Br, F, O, Al, C, Li, Cs and Xe Choose the following:
   (a) the element with six electron in the valence shell.
   (b) the element which belong to zero group.
   (c) The  element which form large no. of compound
2. Out of Li and Be, which is expected to have second ionization enthalpy?

Question: (xxix) The density of 2 molal aqueous solution of NaOH is 1.10 gml^-1. Calculate the molarity of the solution.

OR

The reaction 2C + O₂  →   2CO is carried out by taking 24g of C and 96g of O₂. Find out

1. Which reactant is left in excess.
2. How much of it is left
3. How many gram of other reactant should be taken so that nothing is left at the end of the reaction.

Question: (xxx) Calculate the frequency, wave number and energy associated with the photon of radiation having wavelength 6000A^o.

OR

Draw and explain the line spectrum of Hydrogen atom.

11th CBSE NCERT Chemistry Mid Term Exam – Question: (xxxi)

1. Explain the following term:
   (a) Pauli exclusion principle
   (b) Heisenberg Uncertainty Principal
2. Draw the shape of the orbital in which
   n = 3, l = 2, m₂ = -2

Question: (xxxii)

1. Write the resonating structure for SO₃
2. Arrange the bond in order of increasing ionic character in the molecule LiF, K₂O, N₂, SO₂, ClF₃
3. What is significance of plus and minus sign in representing the orbital.

Question: (xxxiii) A mixture of Hydrogen and Oxygen at 1 bar pressure contain 20% by weight of Hydrogen. Calculate the partial pressure of Hydrogen.

Question: (xxxiv) Calcium Carbonate react with aqueous HCl according to the reaction:

CaCO₃(S) + 2HCl (aq) → Cacl₂(aq) + CO₂(g) + H₂O (l)

What mass of CaCO₃ is required to react completely with 25ml of 0.75 M Hcl.

Section D

Question: (xxxv)

1. How many unpaired electrons are present in SC(Scandium).
2. In a photo electric effect experiment, irradiation of a metal with a light of frequency 5.2 × 10^-19J. Calculate threshold frequency (Vo) of the metal.

OR

1. Write the values of all the four quantum numbers of the last electron of calcium (Z = 20).
2. Explain why chromium has configuration 3d⁵4S¹ and not 3d⁴4S²
3. In the building of the atom, the filling of 4S-Orbital take place before 3d orbital.

Question: (xxxvi)

1. Differentiate between bonding and Anti-bonding Molecular Orbitals.
2. Calculate the bond order and magnetic properties of O2^2- and O₂^– on the basis of Molecular orbital theory.

OR

1. Define Hybridisation.
2. What are the conditions of Hybridisation.
3. Discuss the orbital structure of NH₃ on the basis of Hybridisation.

Question: (xxxvii) A compound on analysis was found to contain the following composition.

Na = 14.31%. S = 9.97%, O = 69.50%, H = 6.22%

Calculate the MF of the compound assuming that the whole of Hydrogen in the compound is present in water of crystallization. Molecular mass of the compound is 322.

1. Define atomic mass unit

OR

1. What are real gases. Discuss the deviation of real gas from ideal behavior?
2. State and explain the Dalton’s law of partial pressure.