Question

Which of the following statements are correct for Boron and Silicon?
(A) Both form carbides which are very hard
(B) Both reacts with metals to form borides and silicides
(C) Both directly combine with halogen
(D) All of these

Answer 1

Because of similar charge/mass ratio and the small size, the element Boron differs from other group 13 members, but it closely resembles the element Silicon, which is the second element of group 14 and they both exhibit diagonal relationship.

Complete answer:
-When we look at the periodic table, the atomic radius, electronegativity ,properties of compounds of some of the diagonally occupying elements will be the same and the elements are said to exhibit diagonal relationship.
- Some of the most important similarities between boron and silicon include that , both possess closer electronegativity values, both of them do not form cation and form only covalent compounds and both exist in amorphous and crystalline state and exhibit allotropy.
- Both Boron and silicon can form carbides which are very hard and used as abrasive.The formation of carbides of boron and silicon can be represented as follows
$C+4B\to {{B}_{4}}C$
$C+Si\to SiC$
- Both boron and silicon can form binary compounds with several metals to form the corresponding borides and silicides and an example can be represented as shown below
$2B+3Mg\to M{{g}_{3}}{{B}_{2}}$
$2Mg+Si\to M{{g}_{2}}Si$
- Both Boron and silicon can readily react with halogens and it can be represented as shown below
$2B+3C{{l}_{2}}\to 2BC{{l}_{3}}$
$Si+2C{{l}_{2}}\to SiC{{l}_{4}}$
Thus all the given statements about Boron and Silicon are correct.

Therefore the answer is option (D) All of these.

Note: It should be noted that, the chlorides of both are liquid, fume in most air and are readily hydrolysed by water and both form numerous volatile hydrides which can spontaneously catch fire on exposure to air and both are easily hydrolysed.