Class 11th Chemistry
The Jammu & Kashmir State Board of School Education
Rehari Colony, Jammu
Class XI Chemistry
Time: 3 Hours Total Marks: 70
General Instructions
1. All questions are compulsory
2. Question nos. 1 to 5 are very short answer questions and carry 1 mark each.
3. Question nos. 6 to 12 are short answer questions and carry 2 marks each.
4. Question nos. 13 to 24 are also short answer questions and carry 3 marks each
5. Question nos. 25 to 27 are long answer questions and carry 5 marks each
6. Use log tables if necessary, use of calculators is not allowed.
Q. 1 Write the formula of the compound Nickel (II) sulphate? [1]
Q. 2 The following reaction is an example of a [1]
4NH3(g)+ 5O2(g) 4NO(g)+6H2O(g)
i) Displacement reaction
ii) Combination reaction
iii) Redox reaction
iv) Neutralisation reaction
(a) (i) and(iv) (b) (ii) and (iii)
(c) (i) and (iii) (d) and (iv)
Q. 3 Give the values for the principal quantum number and magnetic quantum number for the 19th electron of
K (Potassium). [1]
Q. 4 What shapes are associated with sp3
d and sp3
d
2
hybrid orbitals? [1]
Q. 5 2A(g) + B(g )
4C(g) + Heat [1]
What is the effect of adding Heat to a constant volume above equilibrium?
Q. 6 Which of the following has the largest size? Mg, Mg2+, Al3+, Al [2]
Q. 7 Give IUPAC the name and symbol of elements with atomic numbers 110 and 115. [2]
Q. 8 Give reasons: [2]
(i) Anhydrous AlCl3 is covalent but hydrated AlCl3 is electrovalent. Explain
(ii) Boric acid behaves as Lewis acid? Explain
2
Q. 9 N2 N2
+
O2 O2
+
[2]
Why is there an increase in bond order in going from O2 to O2
+ while a decrease in going from N2
to N2
+
?
Q. 10 Calculate the total pressure of a mixture of 8g of O2 (g) and 4g of H2 (g) in a vessel of 1dm3
at
270C. (Atomic mass of O=16gmol-1
and H=1 gmol-1
. R=0.083bar dm3
/K mol). [2]
Q. 11 Give equations to prove the amphoteric nature of water. [2]
OR
Arrange benzene, hexane and ethyne in decreasing order of acidic behaviour.
Also, give reasons for this behaviour.
Q. 12 Balance the following equation in an alkaline medium by half-reaction method. [2]
Cr(OH)3 + IO3
-
I
-
+ CrO4
2-
Q. 13 The wavelength of the first spectral line in the Balmer series is 6561 Å. Calculate the wavelength of
the second spectral line in the Balmer series. [3]
Q. 14 On a ship sailing in the Pacific Ocean where the temperature is 23.4°C, a balloon is filled with 2 L of air.
What will be the volume of the balloon when the ship reaches the Indian Ocean, where the temperature
is 26.1°C? [3]
Q. 15 All C-O bond lengths in CO3
2-
are equal. Account for this observation. [3]
Q. 16 (a): Which of the two is more concentrated and why? 1 M or 1 m aqueous solution of a solute.
[3]
(b) Calculate the total number of molecules of methane present in 1.6 g?
Q. 17 At 60°C, dinitrogen tetroxide is fifty per cent dissociated. Calculate the standard free energy
change at this temperature and at one atmosphere. [3]
Q. 18 What type of isomerism is exhibited by the following pair of compounds? [3]
(i) Ethanol and Methoxy methane
(ii) o-cresol and m-cresol
(iii)Pentan-3-one and pentan-2-one
Q. 19 When a metal X is treated with sodium hydroxide, a white precipitate A is obtained, which is
soluble in an excess of NaOH to give soluble complex B. Compound A is soluble in dilute HCl to
form compound C. The compound A when heated strongly gives D, which is used to extract the metal.
Identify X, A, B, C and D. Write suitable equations to support their identities. [3]
3
Q. 20 Calculate the energy associated with the first orbit of He+
. What is the radius of this orbit?
[3]
Q. 21 Rashmi and Rekha are doing research on the people working with coal tar. According to the
report prepared by them, people who work under prolonged exposure to coal tar suffers from skin
cancer and ask the authorities to vacant the factories. [3]
(a) What is the reason behind people getting infected with skin cancer?
(b) What values are associated with it?
Q. 22 Calculate the enthalpy of combustion of glucose from the following data [3]
Q. 23 [3]
(a) Fish do not grow as well in warm water as in cold water. Why?
(b) Why does rainwater normally have a pH of about 5.6?
(c) Name two major greenhouse gases.
Q. 24 0.2325g of an organic compound was analysed for nitrogen by Duma’s method. 31.7mL of
moist nitrogen was collected at 250C and 755.8mm Hg pressure. Calculate the percentage of N
in the sample. (Aq. The tension of water at 25oC is 23.8mm). [3]
OR
(a) Why cannot sulphuric acid be used to acidify sodium extract for testing S using lead acetate
solution?
(b) Which of the carbocations is most stable and why?
(c) Why does a liquid vaporize below its boiling point in the steam distillation process?
Q. 25 [5]
(a) Convert:
(i) Propene to propane-1,2-diol
(ii) Isopropylbromide to n-propylbromide
https://www.freshersnow.com/board-model-question-papers/
4
(b) An alkene on ozonolysis gives butane-2-one and 2-methyl propanal.Give the structure and
IUPAC name of Alkene. What products will be obtained when it is treated with hot,
concentrated KMnO4?
OR
Complete the equations:
Q. 26 Calculate the pH of a 0.10M ammonia solution. Calculate the pH after 50.0 mL of this solution
if treated with 25.0 mL of 0.10M HCl. The dissociation constant of ammonia, Kb = 1.77 x 10-5
.
[5]
OR
Calculate the pH of the resultant mixtures:
10mL of 0.2M Ca(OH)2 + 25 mL of 0.1 M HCl
Q. 27 Give reasons for the following [5]
(a) Unlike Na2CO3, K2CO3 cannot be prepared by Solvay process. Why?
(b) Why are alkali metals not found in nature?
(c) Sodium is less reactive than potassium, why?
(d) Alkali metals are good reducing agents, Why?
(e) Alkali metals are paramagnetic but their salts are diamagnetic. Why?
OR
Complete the following reactions:
(a) Why does the solubility of alkaline earth metal carbonates and sulphates in water decrease
down the group?
(b) Arrange the following alkali metal ions in decreasing order of their mobility:
Li+
, Na+
, K+
, Rb+
, Cs+
.Explain
(c) NaOH is a stronger base than LiOH. Explain
(d) Why are alkali metals kept in paraffin or kerosene ?
(e) Why does lithium show properties uncommon to the rest of the alkali metals?
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