Class 11 Chemistry Model Question Set A

Which of the following represents the number of molecules present in 0.5 mole of oxygen gas?

a.

b.

c.

d.

What volume of oxygen gas at STP is required for the complete combustion of 2 moles of hydrogen gas?

a. 11.2 L

b. 22.4 L

c. 44.8 L

d. 5.6 L

The maximum number of electrons that can be accommodated in the fourth shell is:

a. 8

b. 18

c. 32

d. 50

Which of the following elements has the highest electronegativity?

a. Nitrogen

b. Oxygen

c. Fluorine

d. Chlorine

The shape of an ammonia molecule (NH₃) is:

a. Linear

b. Trigonal planar

c. Trigonal pyramidal

d. Tetrahedral

What is the oxidation number of chromium in ?

a. +3

b. +4

c. +6

d. +7

At constant temperature, if the pressure of a fixed mass of gas is doubled, its volume becomes:

a. Double

b. Half

c. Four times

d. Unchanged

For an exothermic reversible reaction, an increase in temperature shifts the equilibrium towards:

a. Forward direction

b. Backward direction

c. Both directions equally

d. No change

Which of the following is used as a catalyst in the Contact process?

a. Finely divided iron

b. Nickel

c. Vanadium pentoxide

d. Platinum black

Which metal ion is present at the centre of the haemoglobin molecule?

a. Mg²⁺

b. Fe²⁺

c. Ca²⁺

d. Zn²⁺

Which of the following is the correct molecular formula of benzene?

a. C₆H₁₂

b. C₆H₁₄

c. C₆H₆

d. C₆H₁₀

A sample of 12 g of magnesium is completely burnt in 8 g of oxygen to form magnesium oxide according to the following reaction:

i. Identify the limiting reactant. [2]

ii. Calculate the mass of magnesium oxide formed. [2]

iii. Calculate the mass of excess reactant left after completion of the reaction. [1]

An element has atomic number 17 and mass number 37.

i. Write its electronic configuration in subshell notation. [1]

ii. Calculate the number of protons, neutrons and electrons. [2]

iii. Write the four quantum numbers of its last electron. [2]

The first ionization energies of three hypothetical elements A, B and C are 496, 738 and 1521 kJ/mol respectively.

i. Define first ionization energy. [1]

ii. Which element is most difficult to ionize? [1]

iii. Explain the relationship between atomic size and ionization energy. [2]

iv. Why does ionization energy generally increase across a period? [1]

i. Define hybridization. [1]

ii. Explain the formation of hybrid orbitals. [2]

iii. Predict the shape and bond angle of methane (CH₄). [2]

A current of 2 A is passed through a solution of copper sulphate for 32 minutes 10 seconds using copper electrodes.

i. Write the cathodic reaction. [1]

ii. Calculate the mass of copper deposited at the cathode. [3]

iii. State one industrial application of electrolysis. [1]

(Given: Atomic mass of Cu = 63.5, Faraday constant = 96500 C/mol)

i. State Boyle's law. [1]

ii. Derive the mathematical expression of Boyle's law. [2]

iii. A gas occupies 600 mL at 750 mm Hg pressure. Calculate its volume when the pressure is increased to 1000 mm Hg at constant temperature. [2]

Consider the reversible reaction:

i. Define chemical equilibrium. [1]

ii. Write the expression for equilibrium constant . [2]

iii. State the effect of increasing pressure on the equilibrium position. Give reason. [2]

i. State Avogadro's law. [1]

ii. Derive the ideal gas equation using gas laws. [3]

iii. Write the value of universal gas constant in SI units. [1]

i. What is allotropy? [1]

ii. Write two differences between diamond and graphite. [2]

iii. Why is aluminium extracted by electrolytic reduction rather than by reduction with carbon? [2]

An organic compound A has molecular formula .

i. Write the structural formula and IUPAC name of two possible compounds having this molecular formula. [2]

ii. Identify the type of isomerism shown by these compounds. [1]

iii. Write the chemical equation for the reaction of propene with hydrogen in the presence of nickel catalyst. [2]

A limestone sample of mass 25 g contains 80% calcium carbonate. On strong heating, calcium carbonate decomposes into calcium oxide and carbon dioxide.

i. Calculate the actual mass of calcium carbonate present in the sample. [1]

ii. Calculate the theoretical mass of calcium oxide formed. [2]

iii. Calculate the volume of carbon dioxide produced at 27°C and 760 mm Hg pressure. [3]

iv. Mention one industrial application of calcium oxide. [2]

(Given: Ca = 40, C = 12, O = 16; )

Ammonia is an important industrial chemical used in the manufacture of fertilizers and other nitrogen-containing compounds.

i. Describe the manufacture of ammonia by Haber's process with a balanced chemical equation. [3]

ii. Draw a labelled flow-sheet diagram of the manufacture of ammonia. [2]

iii. Explain the effects of temperature and pressure on the equilibrium of the reaction according to Le-Chatelier's principle. [2]

iv. Write one important use of ammonia. [1]

Benzene is an important aromatic hydrocarbon that undergoes substitution reactions rather than ordinary addition reactions.

i. Define aromaticity. [1]

ii. Explain the structure of benzene with reference to delocalization of electrons. [2]

iii. Explain the mechanism of nitration of benzene with suitable chemical equations. [3]

iv. Write one difference between electrophilic substitution and electrophilic addition reactions. [2]

Sulphuric acid is one of the most important industrial chemicals manufactured by the Contact process.

i. Write the chemical equations involved in the four major steps of manufacturing sulphuric acid by the Contact process. [4]

ii. Explain the role of catalyst in the oxidation of sulphur dioxide. [1]

iii. Why is sulphur trioxide not directly dissolved in water to prepare sulphuric acid? [1]

iv. Mention two industrial uses of sulphuric acid. [2]