Question

Which of the following statements is/are true for ${13}^{th}$ and ${14}^{th}$ group elements?

• A. Orthoboric acid is a weak monobasic Lewis acid.
• B. Boron and silicon can form stable $B^{3+}$ and $S{i}^{4+}$ ions respectively.
• C. Aluminium is the most electro-positive element in the third group of periodic table.
• D. Silicon exhibits very high tendency to form $p\pi -p\pi$ and $d\pi -p\pi$ multiple bonds.

Answer 1

Answer: (A), (C), (D)

The correct options are
A Orthoboric acid is a weak monobasic Lewis acid.
C Aluminium is the most electro-positive element in the third group of periodic table.
D Silicon exhibits very high tendency to form $p\pi -p\pi$ and $d\pi -p\pi$ multiple bonds.

A) Orthoboric acid $\left(H_{3}B{O}_3\right)$ is a Lewis acid. It is a weak monobasic acid.

B) The formation of $B^{3+}$ and $S{i}^{4+}$ ions are very difficult due to very large ionization energy. Hence, ionic compounds of boron and silicon are rare.

C) In the third group, the reduction potential is most negative (-1.66 V) for aluminum. Hence, it is the most electro-positive element.

D) Silicon forms $p\pi -d\pi$ multiple bonds.