What condition results in magma cooling and forming a “glassy” igneous rock?
a)
extremely slow cooling
b)
cooling in the presence of oxygen
c)
extremely rapid cooling
d)
partial melt cooling
e)
extremely high pressure

C

Explanation:

Glassy or vitreous textures occur during some volcanic eruptions when the lava is quenched so rapidly that crystallization cannot occur. The result is a natural amorphous glass with few or no crystals. As magma cools slowly the minerals have time to grow and form large crystals.

Your correct answer is C)  extremely rapid cooling

Explanation:

c is having 4 valence electrons and is bonded to three hydrogens and one sulphur atom, therefore, the number of bond pair is equal to four. as all the valence electrons are used in forming the bonds so, there is no lone pair left on carbon.

s is having 6 valence electrons and is bonded to one other sulfur atom and one carbon atom, therefore, the number of bond pair is equal to 2. as only two valence electrons are used in forming the bonds so, four electrons are left. therefore, two lone pairs are present on s.