How do you balance HCl + Ba(OH)_2 -> BaCl_2 + H_2O?

1 Answer
May 29, 2016

Add a two in front of the HCl and add a two in front of the H_2 O to get

2HCl + Ba(OH)_2 -> BaCl_2 + 2H_2O

Explanation:

When Balancing acid-base reactions, typically you balance the elements which are the salt's cation and anion's first, here the barium and the chlorine, the oxygen next, and the hydrogen should now be balanced.

It is important to know all the valences of the species to make sure you have the salt right, look at the number of hydrogen and the acid and the number of hydroxides on the base for these numbers.

We have,

HCl + Ba(OH)_2 -> BaCl_2 + H_2O

First we consider the barium, there is one on the LHS and one on the RHS, so we're good.

Second we consider the chlorine, there is one on the LHS and two on the RHS, so we need to have two moles/atoms of HCl in the formula.

color{red}2HCl + Ba(OH)_2 -> BaCl_color{red}2 + H_2O

Third we consider the oxygen, since there are two OH's in the barium hydroxide, there are two oxygen on the LHS, we need two on the RHS so there must be two moles/atoms of H_2 O in the formula.

2HCl + Ba(OH)_color{red}2 -> BaCl_2 + color{red}2H_2O

Now we count up the hydrogen's (it should be balanced already).
There are two HCl atoms/moles for two hydrogen and another two in the pair of OH's in the barium hydroxide, for a total of four on the LHS. On the right all the hydrogen is in the H_2 O, since two have two atoms/moles of H_2 O, each of which contains two hydrogens, we have four hydrogens on the RHS, so they are balances.

This is the final form of the equation,
2HCl + Ba(OH)_2 -> BaCl_2 + 2H_2O