A-Level Chemistry

Question 1

What type of bonding exists in a sodium chloride (NaCl) crystal as studied in Singapore A-Level Chemistry?

Accepted Answer

Ionic bonding — electrostatic attraction between Na⁺ and Cl⁻ ions

Answer

Covalent bonding

Answer

Metallic bonding

Answer

Van der Waals forces

Question 2

According to Le Chatelier's Principle, what happens when pressure is increased on the equilibrium N₂ + 3H₂ ⇌ 2NH₃?

Accepted Answer

Equilibrium shifts to the right (towards fewer moles of gas)

Answer

Equilibrium shifts to the left

Answer

No change occurs

Answer

The reaction stops completely

Question 3

What is the hybridisation of carbon in methane (CH₄)?

Accepted Answer

sp³

Answer

sp

Answer

sp²

Answer

sp³d

Question 4

What is the oxidation state of manganese in KMnO₄?

Accepted Answer

+7

Answer

+4

Answer

+5

Answer

+6

Question 5

What is the rate-determining step in a reaction mechanism?

Accepted Answer

The slowest step that determines the overall rate of reaction

Answer

The fastest step

Answer

The step with the most reactants

Answer

The final step of the mechanism

Question 6

In the Singapore A-Level syllabus, what is an SN2 reaction?

Accepted Answer

A bimolecular nucleophilic substitution with a single concerted step, resulting in inversion of configuration

Answer

A first-order substitution

Answer

A free radical reaction

Answer

An electrophilic addition reaction