Given below are two statements. Statement I : The chlorides of Be and Al have Cl-bridged structure. Both are soluble in organic solvents and act as Lewis bases. Statement II : Hydroxides of Be and Al dissolve in excess alkali to give beryllate and aluminate ions. In the light of the above statements, choose the correct answer from the options given below.
To solve the question, we need to analyze the validity of Statement I and Statement II based on chemical principles.
Statement I: "The chlorides of Be and Al have Cl-bridged structure. Both are soluble in organic solvents and act as Lewis bases."
Cl-bridged Structure: Both BeCl2 and AlCl3 indeed form Cl-bridged structures. BeCl2 forms a polymeric chain structure in the solid-state, while AlCl3 forms a dimer in both the solid and gas phases at low temperature.
Solubility in Organic Solvents: Both BeCl2 and AlCl3 are soluble in organic solvents, consistent with their covalent nature.
Lewis Base Behavior: This part of the statement is incorrect. BeCl2 and AlCl3 are actually Lewis acids because they can accept electron pairs, not donate them. Therefore, they do not act as Lewis bases.
Conclusion for Statement I: The part about the chlorides acting as Lewis bases is false, so Statement I is false.
Statement II: "Hydroxides of Be and Al dissolve in excess alkali to give beryllate and aluminate ions."
Dissolution in Alkali: Both Be(OH)2 and Al(OH)3 dissolve in excess alkali. Be(OH)2 forms beryllate ions (\[ \text{Be(OH)}_4^{2-} \]), and Al(OH)3 forms aluminate ions (\[ \text{Al(OH)}_4^- \]).
This behavior is due to the amphoteric nature of the hydroxides, allowing them to react with bases to form complex anions.
Conclusion for Statement II: The statement is true because the reactions described are correct.
Final Conclusion: Statement I is false but Statement II is true. Therefore, the correct answer is:
