Question

Which of the following is not a similarity of beryllium with aluminium?

• A. It becomes passive when treated with conc.$HN{O}_3$.
• B. It forms polymeric covalent hydrides.
• C. Carbonate of Be is extremely stable.
• D. Salts of Be do not impart colour to the flame.

Answer 1

The correct option is C Carbonate of Be is extremely stable.

Beryllium shows resemblance with its diagonally opposite element aluminium.

Points of similarity are-

• Both metals have a tendency to form covalent bonds. Eg; Chlorides of both are being covalent are being soluble in organic solvents.
• Both $BeC{l}_2$ and $AlC{l}_3$ act as Lewis acids and are used as Friedal Kraft's catalyst.
• These two elements have the same electronegativity and polarizing power i.e. charge per radius ration of their ions are very similar.
• They form polymeric covalent hydrides.
  
• They become passive when treated with $conc.HN{O}_3$
• Salts of Be do not impart colour to the flame.
  
• But, the stability of Carbonate of $Be$ is not similar to carbonate of $Al$.Hence, option C is the correct answer.