Aqueous magnesium hydroxide has been used for many uears because it reacts with HCL to produce magnesium chloride

So far I got

Mg(pos. 2 charge)OH2(-1 charge) + HCL >>>>>>> Mg(+2 charge)Cl2(-1 charge) + H2O

did i get that rite?

5 answers

Mg(OH)2 + 2HCl to MgCl2 +2H2O
Why don't u use cross multiply Mg with OH

and have MgOH2 ?
because it is Magnesium Hydroxide, which has a charge of -1 and 2 atoms of both hydrogen and oxygen are needed to neutralize the charge
The only way to balance polyatomic ions is to use paranthesis?
right. The OH ion is a unit consisting of 1 O atoms + 1 H atoms. The O atom has a charge of -2 and the H atom has a charge of +1; therefore, the OH ion has a NET charge of -1 and to show that it is an entity and not separate, we write it as (OH)^-1.