Question

Which is true about $Si{O}_2$?

• A. It is a network solid
• B. It is attacked by molten NaOH and HF
• C. Each Si atom is covalently bonded in a tetrahedral fashion
• D. All of the above.

Answer 1

The correct option is D All of the above.

$Si{O}_2$ is a covalent, 3-D network solid. Each Si atom is covalently bonded in a tetrahedral manner to four oxygen atoms.
Silica is attacked only by HF and NaOH and It resists the attack by halogens, dihydrogen and most of the acids and metals even at elevated temperatures.
$Si{O}_2+4HF\to Si{F}_4+2H_{2}O$
$Si{O}_2+2NaOH\to N{a}_{2}Si{O}_3+H_{2}O$
Hence, option (d) is the correct answer.