Question

If 0.10 mole of SiO2 and 0.20 mole HF are combined in the reaction SiO2 + 4HF => SiF4 + 2H2O which of these statements is FALSE? A. HF is the limiting reactant. B. Some SiO2 will be left over. C. The theoretical yield of SiF4 is 0.10 mole. D. More HF would be needed to ensure that all the reactants are used up. E. The theoretical yield of H2O will be 0.10 mole.

Answer 1

C. The Theoretical yield of SiF4 is = 0.10

Step-by-step explanation:

A. is TRUE

0.10 mol SiO2 * 4 mol HF/mol SiO2 = 0.40 mol HF which we do not have. Hence, HF is the limiting reagent

B. is TRUE

Some Sio2 will be left over is true since our limiting reagent is HF

C. is FALSE

0.020 mol HF * 1 mol SiF4 produced/ 4 mol HF = 0.05 mol SiF4 produced

Since the mol of SiF4 produced by the limiting reagent HF is given in the ratio of 1/4 it follows that 0.05 mol SiF4 will be produced and no 0.10 therefore statement is FALSE

D. is TRUE

Since HF is the limiting reagent is True that more HF will be needed to react completely with HF (exactly 0.20 mol HF) .

E. is TRUE

The theoreical yield of wate is 0.10 mol TRUE

0.05 mol SiO2 * 2 mol H2O/ mol SiO2 = 0.10 mol H2O