Question

Silica reacts with Hydride of superhalogen to form $'X'.$ On hydrolysis of $'X'$ another compound $ 'Y'$ is formed. $'Y'$ on heating at $1000^{\circ} C$ loses water to form ' $Z$ '. The $'Z' $ can also be prepared in the following reaction.

• A. $SiO _{2}+4 HF \rightarrow SiF _{4}+2 H _{2} O$
• B. $Si + O _{2} \rightarrow SiO _{2}$
• C. $K _{2} SiF _{6}+4 K \rightarrow 6 KF + Si$
• D. $Si +2 NaOH + H _{2} O \rightarrow Na _{2} SiO _{3}+2 H _{2}$

Answer 1

Answer: (B)

Hydride of super halogen $= HF$

$SiO _{2}+4 HF \rightarrow \underset{(X)}{SiF _{4}}+2 H _{2} O$

$3 SiF _{4}+4 H _{2} O \rightarrow \underset{(Y)}{H _{4} SiO _{4}}+2 H _{2} SiF _{6}$

$H _{4} SiO _{4} \stackrel{1000^{\circ} C }{\longrightarrow } \underset{(Z)}{SiO _{2}}+2 H _{2} O$

$X = SiF _{4}, Y = H _{4} SiO _{4}, Z = SiO _{2}$

$Si + O _{2} \rightarrow SiO$