Question

What is the formula of silver glance?
A.$AgCl$
B.$Ag_{2}S$
C.$SiO_{2}$
D.$AgNO_{3}$

Answer 1

Hint: Silver glance is a black-grey cubic silver sulfide mineral. It is an important constituent of silver ore and contains almost 87% silver and around 12.94% sulfur. Silver glance is also known as Argentine.

Complete answer:
- Silver glance or Argentine is the most important silver ore after galena. Galena is a lead ore that contains about 1% silver.
- The chemical formula of silver glance is $Ag_{2}S$, and the chemical name is silver sulfide. It is sulfide ore of silver. Its color is lead-grey to black.
- Its molecular weight is 447.80 g. it contains silver in about 87.06% and sulfur in 12.94%.
- It has an isometric structure and is stable only at temperatures above 173 degree Celsius.
- The argentine word comes from the Latin word for silver, Argentum, from which the chemical symbol for silver, Ag, is also derived.
- It has a metallic luster with opaque crystals.
- Silver glance is sectile, which means it can be cut with a knife, like lead and fresh shiny surfaces will eventually form a dull coating after prolonged exposure to light.
- It is termed so because it contains silver in large amounts and another constituent than silver is sulfur only.

Therefore, the correct answer is (B).

Note:
When silver glance cools to normal temperature, it turns into its monoclinic polymorph called ‘acanthite’. Thus, we can say that it is the high-temperature form of acanthite.