Which of the following fluoro-compounds is most likely to behave as a Lewis base ?

The suspension of slaked lime in water is known as

Zinc can be coated on iron to produce galvanized iron but the reverse is not possible. It is because

AIF₃ is soluble in HF only in presence of KF. It is due to the formation of

Boric acid is an acid because its molecule

(1) Combines with proton from water molecule

(2) Contains replaceable H⁺ ion

(3) Gives up a proton

(4) Accepts Om water releasing proton