A compound among the following that is least likely to behave as a Lewis base is:

1.	NH3	2.	BF3
3.	OH-	4.	H2O

Which one of the following anions is present in the chain structure silicates?

1. $S{i}_2{O}_7^{6-}$

2. $\left(S{i}_2{O}_5^{2-}\right)n$

3. $\left(Si{O}_3^{2-}\right)n$

4. $Si{O}_4^{4-}$

Al₂O₃ can be converted to anhydrous AlCl₃ by heating:

1. $A{l}_2{O}_3$ $with$ $HCl$ $gas$

2. $A{l}_2{O}_3$ $$with NaCl in solid-state

3. a mixture of $A{l}_2{O}_3$ $$ and carbon in dry $C{l}_2$ gas

4. $A{l}_2{O}_3$ $$ with $C{l}_2$ gas

The basic structural unit of silicates is:

1. (SiO₄)^4–

2. (SiO₃)^2–

3. (SiO₄)^2–

4. (SiO)

Which of the following is not a monomer for a high molecular mass silicone polymer?

A compound among the following having a similar structure to graphite is:

1. B
2. B₄C
3. B₂H₆
4. BN

The stability of +1 oxidation state among Al, Ga, In and Tl increases in the sequence?
1. Ga < ln < Al < Tl
2. Al < Ga < ln < Tl
3. Tl < ln < Ga < Al
4. ln < Tl < Ga < Al

Which of the following oxide is amphoteric?

1. CO₂ 

2. SnO₂

3. CaO 

4. SiO₂