Boric acid is not used:

1. As an antiseptic

2. As a flux in soldering

3. In making optical glasses

4. In making enamels and pottery glazes

An incorrect statement among the following regarding Al₂Cl₆ is:

Heating an aqueous solution of aluminium chloride to dryness will give:

1.  ${\mathrm{AlCl}}_3$

2.  ${\mathrm{Al}}_2{\mathrm{Cl}}_6$

3.  ${\mathrm{Al}}_2{\mathrm{O}}_3$

4.  $\mathrm{Al}\left(\mathrm{OH}\right){\mathrm{Cl}}_2$

Carbon dioxide is a gas but silica is a solid because:

1.  carbon dioxide is composed of discrete covalent ${\mathrm{CO}}_2$ molecules whereas silica has continuous

     tetrahedral structure

2.  ${\mathrm{CO}}_2$ molecules are lighter than ${\mathrm{SiO}}_2$ molecules

3.  ${\mathrm{CO}}_2$ is more acidic than ${\mathrm{SiO}}_2$

4.  melting point of silica is very high

The greatest percentage of $\mathrm{CO}$ is in:

1.  coal gas

2.  producer gas

3.  water gas

4.  oil gas

Which of the following shows bond in silicone?

1.  $\mathrm{Si}—\mathrm{C}—\mathrm{Si}—\mathrm{O}—\mathrm{Si}$

2.  $\mathrm{Si}—\mathrm{C}—\mathrm{Si}—\mathrm{C}—\mathrm{Si}$

3.  $—\stackrel{\mathbf{|}}{\mathrm{Si}}—\mathrm{O}—\stackrel{\mathbf{|}}{\mathrm{Si}}—\mathrm{O}—\stackrel{\mathbf{|}}{\mathrm{Si}}—$

4.  $\mathrm{Si}—\mathrm{Si}—\mathrm{Si}—\mathrm{Si}$

Mica is chemically:

1.  potassium alumino silicate having sheet structure

2.  calcium alumino silicate having fibrous structure

3.  calcium magnesium silicate having three dimensional network

4.  hydrated sodium alumino silicate having three dimensional network

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]

Silicon carbide is used as:

${\mathrm{Mg}}_2{\mathrm{C}}_3$ has the following characteristics:

1.  It is called magnesium allylide

2.  It contains ${\mathrm{Mg}}^{2+}$ and ${\mathrm{C}}_3^{4-}$ions

3.  It on hydrolysis gives propyne

4.  All of the above