Chemistry Model Questions Solution
Subject Code : Che. 301
Full marks: 75
Time :3 hours
Attempt all questions
Group 'A'
Circle the best alternative to the following questions. (11×1 = 11)
1. How many atoms are there in two molecules of water?
a. 3
b. 4
c. 5
d. 6
2. What is the number of moles of ammonia gas formed when 0.5 mole of nitrogen
gas is reacted with excess of hydrogen gas?
a. 0.5
b. 1
c. 2
d. 3
3. Which of the following bonding is responsible for the solubility of ammonia gas
in water?
a. Hydrogen bonding
b. Ionic bonding
c. Covalent bonding
d. Van der Waals' force
4. What happens when Sulphur dioxide (SO2) gas is passed through an acidified
solution of hydrogen sulfide (H2S) gas?
a. SO2 is oxidized to Sulphur
b. H2S is reduced to Sulphur
c. SO2 is oxidized to H2SO4
d. SO2 is reduced to Sulphur
5. Which of the following property of crystalline substance describes the similar
chemical composition?
a. Isotopism
b. Isotopism
c. Allotropism
d. Isomorphism
6. SO3 gas is formed as an intermediate during the manufacture of Sulphuric acid
by contact process. The formation of Sulphur trioxide from sulfur dioxide and
oxygen is reversible.
2SO2 + O2 ⇌ 2SO3 ∆H = –196 kJ mol–1
Which conditions of pressure and temperature favor the reverse reaction?
a. High pressure and high temperature
b. High pressure and low temperature
c. Low pressure and high temperature
d. Low pressure and low temperature
7. Which is the correct order of ease of carbon dioxide production by heating the
Group II metal carbonates?
a. MgCO3 >BeCO3>CaCO3>RaCO3
b. CaCO3 >MgCO3 >BeCO3>RaCO3
c. BeCO3>MgCO3 >CaCO3>BaCO3
d. BeCO3 <MgCO3 <CaCO3<RaCO3
8. Which of the following is related to Batch process?
a. Requires high- cost equipment
b. Can -not be controlled easily
c. Generally available in fully automated plant
d. Involves sequence of steps followed in specific order
9. Sodium-glucose pump is an example of
a. Primary active transport protein
b. Secondary active transport protein
c. Primary passive transport protein
d. Secondary passive transport protein
10. An intermediate compound X is formed during the production of urea through
ammonia/carbon dioxide technology. What is the molecular formula of X?
a. NH2COONH2
b. NH2COONH4
c. NH4COONH2
d. NH4COONH4
11. Which of the following are recycled in the manufacture of sodium Carbonate
by Solvay’s process?
a. CO2 and NH4Cl
b. CO2 and NH3
c. NaCl and CaO
d. NaCl and NH3
Group 'B'
Give short answer to the following questions. (8 × 5=40)
1. An element X has 2 electrons in K shell, 8 electrons in L shell and 5 electrons in
M shell.
i. Identify the element X and write the number of protons and electrons in
it. [3]
ii. Size of X- - - ion is greater than that of X atom though both contain the
same number of protons. Give reason [1]
iii. c. Write down the formula of one of the compounds of X where X is in -3
oxidation state. [1]
OR
Know -how about ionization energy (IE) of elements is crucial aspect in the
study of chemical bonding whether they form ionic or covalent bond. The first
ionization energies of period second elements are given below
Name of elements Li Be B C N O F Ne
First ionization energy(kJ/mol) 520 899 801 1086 1403 141011681 2080120
i. Define first ionization energy. [1]
ii. Name a factor that affects the value of IE. [1]
iii. Which of the element is most difficult to ionize? [1]
iv. Why is there steep rise in IE from carbon to nitrogen? [2]
2. When electricity is passed through the molten NaCl in the presence of CaCl2 in
the ration of 2:3 by weight using graphite anode and iron cathode as electrodes,
sodium metal is deposited at cathode and chlorine gas is liberated at anode in the
electrolytic cell
i. Define electrolytic cell. [1]
ii. Find the mass of sodium metal deposited at cathode when 0.1 ampere of
current is passed for half an hour and the process has 75% efficiency. [2]
iii. Why does calcium metal not deposit instead of sodium at the cathode? [1]
iv. Aqueous solution of sodium chloride cannot be instead of molten sodium
chloride for the same intended product? Give reason. [1]
3. Derive the relationship between Kp and Kc. Give one example of chemical
reaction where Kp is greater than Kc [4+1]
OR
Derive the ideal gas equation PV=nRT where the symbols have their usual
meaning. State two conditions under which behavior of real gas approaches
that of an ideal gas. [3+2]
4. Concentrated sulphuric acid can be used in the laboratory to produce hydrogen
chloride gas by the reaction with solid sodium chloride.
i. Hydrogen iodide is not produced by the same method as for hydrogen
chloride. Why? [1]
ii. What is the difference between hydrogen chloride gas and hydrochloric
acid? [2]
iii. How could you identify the bottle containing HCl using ammonia gas?
[2]
5. Depending upon the nature of minerals present in the ores, calcination and
roasting are mainly used for the conversion of ores into their respective oxides.
i. What do you mean by roasting and calcination in the metallurgical
process? [2] 121
ii. Name the vessel in which roasting is carried out [1]
iii. Write the name of two possible impurities that are removed in the
roasting [2]
6. One of the examples of homologous series is given below.
CH3OH
CH3CH2OH
X
CH3CH2CH2CH2OH
i. Define homologous series. [1]
ii. Find the mass difference between successive member of above
homologous series and calculate the molecular mass of X [2]
iii. What is the reason behind the highest boiling point but least solubility of
the fourth member in the given series? [2]
7. An unsaturated hydrocarbon B upon treatment with Hydrogen bromide produces
compound C. Compound C reacts with sodium metal in the presence of organic
ether produces compound D of molecular formula C6H14.
i. Give the chemical equations for the conversion of compound B to
compound C and compound C to compound D [2]
ii. Write down the IUPAC name of compound C and D [2]
iii. Give the structural formula of positional isomer of compound C [1]
8. Urea is a very much demanded chemical fertilizer in agricultural country like
Nepal because of the lack of domestic production. One of the raw materials for
urea production is ammonia which is obtained from Haber’s process.
i. Draw a flow sheet diagram for the manufacture of Ammonia by Haber’sBosch Process [3]
ii. What is the major challenge in establishing chemical industries in the
countries like Nepal? Mention how such challenge can be strategically
overcome? [2]
Group 'C'
Give long answer to the following questions (3× 8=24)
9. In the presence of platinum catalyst ammonia is oxidized to nitric oxide. The
reaction is given below.
4NH3+ 5O2 pt→ 4NO + 6H2O
i. Calculate the mass of Nitric oxide produced by the reaction of 2 mole of
ammonia with 2 moles of oxygen. [2]
ii. What is the importance of limiting reactant in chemical calculation? [1]
iii. If 2 moles of ammonia produce 50 grams of water upon reaction with
excess of ammonia. what is the percentage yield of the reaction? [2]
iv. Calculate the volume of HCl gas required at 200
c and 750mm Hg pressure
which can completely react with 2 mole of ammonia gas to produce
ammonium chloride [3]
10. Oxygen is the third most abundant element by mass which readily forms oxides
with other elements. Some of the oxides are given below
Na2O Al2O3 CO SO2 Fe3O4 H2O2
i. Identify the acidic oxide, basic oxide, neutral oxide and mixed oxide
from the above table [4]
ii. Write two chemical equation to prove that the particular oxide is
amphoteric in nature. [2]
iii. Why is CO a harmful gas? [1]
iv. Write any one industrial applications of oxygen gas. [1]
OR
Sulfuric acid is one of thelargest volumes of industrial chemical produced in the
world. Over the last decades the contact process has been used to produce
sulfuric acid, replacing the traditional (Lead Chamber) process.
i. Write the four steps of chemical equation for the manufacturing of
sulphuric acid by contact process starting form iron sulfide. [4]
ii. Give any two chemical equations in which sulphuric acid acts as
precipitant and dehydrating agent. [2]123
iii. Write the chemical equation producing fertilizer using H2SO4 [1]
iv. Why does H2SO4 always act as an oxidizing agent? [1]
11. An alkene X undergoes ozonolysis and gives two compounds Y and Z of
molecular formula C3H6O. Y and Z are functional isomers of each other
i. Write the two-steps chemical equation for the conversion of X into Y and
Z. [2]
ii. Write the structural formula of Y and Z. Why are they called functional
isomers? [3]
iii. What happens when hydrogen gas in the presence of nickel catalyst is
passed over X? [1]
iv. What is the application of ozonolysis in the organic reaction mechanism?
[1]
v. How can you prove chemically the compound X is unsaturated? [1]
End
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