Question

The compound that is used for etching of glass is:
A.$HI$
B.$HBr$
C.$HCl$
D.$HF$

Answer 1

Etching is defined as the process in which art work or designs are made on the plates or any other object by using the corrosive action of an acid.

Complete step by step answer:
-Etching is a process used for making designs on plates or any other object . To make the artwork corrosive action of an acid is required on the object .
-Let’s see how this works :
-Glass is made up of sand which consists mostly of silicon dioxide.
-This sand is heated and melted and gets converted to liquid.
-Later on this liquid sand is used to make a glass.
Now we will see the process of etching of glass:
-Firstly, the glass is coated with the layer of beeswax or paraffin on which designs or patterns are traced with the help of metal needles.
-Then this glass is dipped in hydrofluoric acid $HF$ solution. It etches the designs or pattern through the grooves made by the needles in the layer of protective coating.
-The reaction of etching of glass is given as follows:
$4HF + Si{O_2} \to Si{F_4}_{\left( g \right)} + 2{H_2}O$ .
The reason why $HF$ (hydrofluoric acid) is used in the etching of glass, is because there is a strong bond formation between the fluoride anions and silicon molecules that is present in the glass.
So, the correct answer is option D) $HF$ (hydrofluoric acid) .

Note:
$HF$ (hydrofluoric acid) is the only compound that can etch through the glass because it can easily dislocate oxygen easily from silicon dioxide whereas $HI$ , $HBr$ ,$HCl$ does not react with the glass. That is why we can store acids in the glass containers easily.