Question

How many grams of HCI would be required to dissolve 18g of Fe2O3? Fe2O3 + 6HCI → 2Fe Cl3 + 3H2O.

Answer 1

Answer: 21.9 g

Given the chemical formula:

Fe₂O₃ + 6HCl → 2FeCl₃ + 3H₂O

Here, We are given the mass of Fe₂O₃ to be 18g.

We know,

Mass of:

Fe = 56 g , Cl = 35.5 g , H = 1 g, O = 16 g

⇒ Molecular mass of Fe₂O₃ = 2

⇒ Molecular mass = 2×56 + 16×3

⇒ Molecular mass = 112 + 48

⇒ Molecular mass = 160 g

Now,

⇒ Number of moles = Mass given / Molar mass

⇒ no. of moles = 18 / 160

⇒ no. of moles = 0.11 mol

From the chemical equation,

⇒ 6 mol of HCL is required to dissolve 1 mol of Fe₂O₃

∴ HCl required to dissolve 0.11 mol = 6 × 0.11

⇒ HCl required = 0.6 mol

Again,

⇒ no. of moles = Mass given / molar mass

⇒ 0.6 = Mass given / 36.5 [ Molar mass of HCl = 36.5 g ]

⇒ Mass = 36.5 × 0.6

⇒ Mass = 21.9 g

Hence, 21.9 g of HCl is required to dissolve 18 g of Fe₂O₃ .

Some Information :-

☛ No. of moles = Mass given / Molar mass

1 mole of something has 6.023 × 10²³ atoms/molecules

☛ Molecular weight = 2 × Vapour Density