Class 11 Chemistry Model Question Set C

Which of the following represents the number of molecules present in 0.25 mole of oxygen gas?

a.
b.
c.
d.

The maximum number of electrons that can be accommodated in a shell with principal quantum number is:

a. 8
b. 18
c. 32
d. 9

Which of the following has the highest bond order?

a.
b.
c.
d.

The oxidation number of sulphur in is:

a. +4
b. +5
c. +6
d. +7

Which gas is most easily liquefied under ordinary conditions?

a. Hydrogen
b. Helium
c. Ammonia
d. Nitrogen

For a reaction at equilibrium, the value of equilibrium constant changes with:

a. Concentration
b. Pressure
c. Catalyst
d. Temperature

Which of the following is an acidic oxide?

a.
b.
c.
d.

Which metal is commonly used as a sacrificial anode to protect iron from corrosion?

a. Copper
b. Zinc
c. Silver
d. Gold

The IUPAC name of is:

a. Butan-1-ol
b. 2-Methylpropan-1-ol
c. 2-Methylpropan-2-ol
d. Butan-2-ol

Which of the following is an example of an electrophile?

a.
b.
c.
d.

The main purpose of adding gypsum during cement manufacture is to:

a. Increase the colour of cement
b. Increase the strength immediately
c. Control the setting time
d. Reduce the cost of limestone

(a) Define limiting reagent. [1]

(b) When 4.8 g of magnesium reacts with 6.4 g of oxygen, calculate: [3]

i. The limiting reactant ii. The mass of magnesium oxide formed

(c) State one practical application of stoichiometry. [1]

(a) Define de Broglie wavelength. [1]

(b) Calculate the de Broglie wavelength of an electron moving with a velocity of . Given: , . [2]

(c) Why does electron affinity generally become more negative across a period? [2]

(a) What is hybridization? [1]

(b) Explain the hybridization and shape of molecule. [2]

(c) Why is the bond angle of smaller than that of ? [2]

(a) What is disproportionation reaction? [1]

(b) Identify oxidation and reduction in the following reaction. [2]

(c) Give two applications of redox reactions in daily life or industry. [2]

(a) State Dalton's law of partial pressure. [1]

(b) A mixture of hydrogen and oxygen contains 2 moles of hydrogen and 1 mole of oxygen. If the total pressure is 900 mm Hg, calculate the partial pressure of each gas. [2]

(c) Explain why the boiling point of water is unusually high compared with that of hydrogen sulphide. [2]

(a) Define Le Chatelier's principle. [1]

(b) Consider the equilibrium: [2]

Predict the effect of:

i. Increasing pressure
ii. Increasing temperature

(c) Explain the effect of a catalyst on the equilibrium position. [2]

(a)

pH is defined as the negative logarithm (base 10) of the hydrogen ion concentration of a solution.

Mathematically,

(b)

Given:

• Concentration of HCl =

• HCl is a strong acid and completely ionizes in water.

Step 1: Write the ionization equation.

Therefore,

Step 2: Apply the pH formula.

Using logarithmic properties:

Final Answer

The pH of the HCl solution is 3.

(c)

Ionization equations:

Strong acid:

Weak acid:

(a) What is catenation? [1]

(b) Explain why nitrogen exists as a diatomic molecule while phosphorus commonly exists as 𝑃 4 P 4 . [2]

(c) Write two differences between roasting and calcination. [2]

a) Define homolytic fission. [1]

(b) Explain the difference between electrophiles and nucleophiles with one example of each. [2]

(c) Write the equations for the preparation of ethyne from calcium carbide and its reaction with bromine. [2]

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]