Answer to Question #249590 in General Chemistry for grey tyrant

Question

The use of hydrofluoric acid for etching and frosting of glass is based on the fact that it attacks glass, silicon dioxide. Silicon tetrafluoride and water are produced.

SiO2 + 4 HF → SiF4 + 2 H2O

a. Write the mode of action.

b. Calculate the number of moles of hydrofluoric acid would completely react with 2.5 moles of silicon dioxide

Answer 1

SiO₂⁺+4HF^--->>SiF₄⁺+2H₂O^-

Mole ratio SIO2:HF = 1:4

= 4×2.5= 10 moles of HF