Question

Balance the following equation: $Ba{\left( {OH} \right)_2} + HBr \to BaB{r_2}\left( {aq} \right) + {H_2}O\left( l \right)$

Answer 1

Hint: In a chemical reaction we do not change the quantity of each element. Thus, each side of the element must represent the same quantity of any particular element. If we try changing the scalar number for each molecular formula the equation might get balanced. We use the hit and try method for such type of equations.

Complete Step by step answer: First, we need to see if the number of atoms is equal on both the sides of the equation.
$Ba{\left( {OH} \right)_2} + HBr \to BaB{r_2}\left( {aq} \right) + {H_2}O\left( l \right)$

Atoms in reactants	Atoms in product
$ Ba = 1 \\ O = 2 \\ H = 4 \\ Br = 1 \\ $	$ Ba = 1 \\ Br = 2 \\ H = 2 \\ O = 1 \\ $

Hence the above equation is not balanced as the number of atoms are not equal on both the sides. Now we will try to equal the number of atoms on both side: -

\[Ba{(OH)_2}\] $ + $	$HBr \to $	$BaB{r_2}(aq)$ $ + $	${H_2}O(l)$
$ Ba = 1 \\ O = 2 \\ H = 2 \\ $	\[ \;H = 1 \times 2 = 2 \\ Br = 1 \times 2 = 2 \\ \]	$ Ba = 1 \\ Br = 2 \\ $	$ H = 2 \times 2 = 4 \\ O = 1 \times 2 = 2 \\ $

The atoms on both the sides are now balanced.We will place $2$ before the ${H_2}O$ molecule in order to balance the hydrogen and oxygen atoms. Each atom in ${H_2}O$ molecule will be multiplied by $2$ .Next, we will place $2$ before $HBr$ to balance the $Br$ and $H$ atom. Each atom in $HBr$ molecule will be multiplied by $2$ .
Hence the correctly balanced equation will be: -
$Ba{\left( {OH} \right)_2} + 2HBr \to BaB{r_2}\left( {aq} \right) + 2{H_2}O\left( l \right)$

Note: To balance an equation you change the coefficients, not the subscripts in the formulas. Do not change numbers that are already a part of the chemical formula. You should always balance polyatomic ions as a whole. Never put the coefficients in the middle of the formula, they always must go in front of the entire molecule