An amphoteric  oxide among the following is-

1. CO₂

2. CO

3. SnO₂

4. CaO

The element among the following that does not show inert pair effect is-

Borax is converted into crystalline boron by the following steps:

          $\mathrm{Borax}\stackrel{\mathrm{X}}{\to }{\mathrm{H}}_3{\mathrm{BO}}_3\stackrel{∆}{\to }{\mathrm{B}}_2{\mathrm{O}}_3\underset{∆}{\overset{\mathrm{Y}}{\to }}\mathrm{B}$

X and Y are respectively :

1. HCl, Mg                                 
2. HCl, C
3. C, Al 
4. HCl, Al

The incorrect statement among the following regarding borax is-

1. It is a useful primary standard for titrating against acids. 

2. One molecule of borax contains 4 \(B — O — B\) bonds.

3. Aqueous solution of borax can be used as a buffer.

4. It is made up of two triangular \(BO_{3}\) units and two tetrahedral \(BO_{4}\) units.

The species among the following that does not exist is-

1. ${\left(\mathrm{Sn}{F}_6\right)}^{2-}$

2. ${\left({\mathrm{GeCl}}_6\right)}^{2-}$

3. ${\left({\mathrm{CCl}}_6\right)}^{2-}$

4. ${\left({\mathrm{SiF}}_6\right)}^{2-}$

$\mathrm{RCl}$ $\underset{\mathrm{Si}}{\overset{\mathrm{cu}-\mathrm{powder}}{\to }}{\mathrm{R}}_2{\mathrm{SiCl}}_2\stackrel{{\mathrm{H}}_2\mathrm{O}}{\to }$
${\mathrm{R}}_2\mathrm{Si}{\left(\mathrm{OH}\right)}_2$ $\stackrel{\mathrm{condensation}}{\to }$ $\mathrm{A}$

Compound (A) is -

An Aqueous solution of borax reacts with 2 moles of acid due to -

1. Formation of 2 moles of  B(OH)₃  only

2. Formation of 2 moles of  [B(OH)₄]^-  only

3. Formation of 1 mole each of  B(OH)₃ and [B(OH)₄]^-

4. Formation of 2 moles each of [B(OH)₄]^- and B(OH)₃, only [B(OH)₄]^-  reacts with an acid 

The incorrect statement among the following is -

1. $\mathrm{Ge}{\left(\mathrm{OH}\right)}_2$ is amphoteric

2. ${\mathrm{GeCl}}_2$ is more stable than ${\mathrm{GeCl}}_4$

3. ${\mathrm{GeO}}_2$ is weakly acidic

4. GeCl₄ + 2HCl ⇄ H₂[GeCl₆]

The correct statement regarding polymeric silicon dioxide is -

The correct statement among the following is :