Mellitic acid is formed by the oxidation of graphite with -

1. Chromic acid

2. Alkaline ${\mathrm{KMnO}}_4$

3. Fuming ${\mathrm{HNO}}_3$

4. dil. ${\mathrm{HNO}}_3$

Select the correct statement(s) regarding the following reaction sequence:

 
   

1.  The compound (A) is ${\left({\mathrm{CH}}_3\right)}_2{\mathrm{SiCl}}_2$

2.  The compound D is SiC

3.  The compound (B) is ${\left({\mathrm{CH}}_3\right)}_2\mathrm{Si}{\left(\mathrm{OH}\right)}_2$

4.  All of the above

Carbogen is:

1.  A mixture of ${\mathrm{O}}_2+5-10\% of {\mathrm{CO}}_2$.

2.  Used by pneumonia patients for respiration.

3.  Used by victims of $\mathrm{CO}$ for respiration.

4.  All of the above.

Amphoteric oxides are:

1. Tl₂O₃, SiO₂

2. ${\mathrm{CO}}_2$, ${\mathrm{B}}_2{\mathrm{O}}_3$

3. ${\mathrm{B}}_2{\mathrm{O}}_3$, ${\mathrm{SiO}}_2$

4. Al₂O₃ , PbO₂

The sharp decrease in ionization enthalpy from carbon to silicon happens because of-

The basic structural unit of silicates is-

The incorrect statement among the following options is-

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

The amphoteric oxide among the following is -

The reason behind carbon showing catenation property but lead does not is:

1. Due to the smaller size of C than that of Pb

2. Due to the smaller size of Pb than that of C

3. Due to the smaller ionization energy of C than that of Pb

4. Due to the inert pair effect