Question

How much water is formed when 1.0 mol of `HCl` reacts completely with 1.0 mol of `NaOH`?

Answer 1

Assume that:
n = number of moles
m = mass of substance
M = molar mass

Looking at the equation:
`HCl + NaOH => H_2O + NaCl`.

Since all compounds in this reaction have 1 mole, it will not affect the number of moles (n).

If 1 mole of HCl or NaOH gives you 1 mole of `H_2O`, then the number of moles in `H_2O` is: [`1 -: 1 xx 1`] = 1 mole.

Now you have to find out the molar mass (M) of water (`H_2O`).
Before that, take note that you know what atoms are present in `H_2O` - in that case, hydrogen and oxygens are present.

Refer to your periodic table and you can see molar mass of (?) is:
Hydrogen = 1.0 g/mol
Oxygen = 16.0 g/mol

Therefore the molar mass (M) of `H_2O` is:
[`2 xx 1.0 + 1 xx 16.0`] = 18.0 g/mol.

Last step, find the mass (m) of water.
The formula of finding mass of substance (m) is:
`m = n xx M`.
The mass of `H_2O` is: [m = 1.0 moles `xx` 18.0 g/mol = 18.0 grams]

Therefore 18.0 grams of water is formed when 1 mole of HCl reacts completely with 1 mole of NaOH.