Multiple Choice

Which of the following can act as Lewis acid?

A$$SiF_4$$
Correct Answer
B$$SnCl_4$$
Correct Answer
C$$CCl_4$$
D$$SF_4$$
Correct Answer

Solution

Lewis Acid: A species that accepts an electron pair (i.e., an electrophile) and will have vacant orbitals.
Lewis acids accept an electron pair. Lewis Acids are electrophilic meaning that they are electron attracting. When bonding with a base the acid uses its lowest unoccupied molecular orbital
Various species can act as Lewis acids. All cations are Lewis acids since they are able to accept electrons. (e.g., $$Cu^{2+}, Fe^{2+}, Fe^{3+}$$)
An atom, ion, or molecule with an incomplete octet of electrons can act as an Lewis acid (e.g., $$BF_3, AlF_3$$).
Molecules where the central atom can have more than 8 valence shell electrons can be electron acceptors due to the presence of empty d-orbitals, and thus, are classified as Lewis acids (e.g., $$SiBr_4, SiF_4, SnCl_4, SF_4$$).
Molecules that have multiple bonds between two atoms of different electronegativities (e.g., $$CO_2, SO_2$$)
But in $$CCl_4$$ there is no vacant d-orbitals available for carbon.
Hence options A,B & D are correct.


SIMILAR QUESTIONS

Chemical Bonding

$$BF_{3}$$ forms an adduct with $$NH_{3}$$ because:

Chemical Bonding

PF$$_{3}$$ can act as a donor molecule while NF$$_{3}$$ shows little tendency to act as a donor. This is because in PF$$_{3}$$, lone-pair on P is easily donated compared to that of N.

Chemical Bonding

Which of the following molecule is not hypovalent

Chemical Bonding

Which of the following does not contain any coordinate bond?

Chemical Bonding

Which one of the following does not have a pyramidal shape?

Chemical Bonding

Which of the following does not contain any coordinate bond?

Chemical Bonding

Explain the following on the basis of valence bond theory: $$BF_{3}$$ is planar but $$NH_{3}$$ is not.

Chemical Bonding

$$BF_3$$ has less lewis acidic property than $$BBr_3$$ . Why ?

Chemical Bonding

$$(CH_3)_3$$ COH is less acid than $$(CH_3)_3$$ SiOH. Why ?

Chemical Bonding

In co-ordinate bonds, the acceptor atoms must essentially contain in its valency shell an orbitial:

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