IB Chemistry HL R3.4 Electron-pair sharing reactions questions

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Question 1

Paper 2Medium6 marks

Boron trifluoride forms a 1:1 adduct with ammonia:

Reaction I: BF₃ + NH₃ → BF₃·NH₃

A proton reacts with water to form a hydronium ion:

Reaction II: H⁺ + H₂O → H₃O⁺

(a)

Identify the electrophile in reaction I and state which reactant supplies both electrons in the new B–N bond.

[2]
(b)

Identify the electrophile in reaction II and explain the origin of both electrons in the new O–H bond.

[2]
(c)

A student claims that an electrophile must be positively charged. Assess this claim using both reactions.

[2]

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