A0.784 g sample of magnesium is added to a 250 ml flask and dissolved in 150ml of water. magnesium hydroxide obtained from the reaction required 215.0 ml of 0.300 m hydrochloric acid to completely react. how many moles of mg were used?

The chemical reaction involving Mg(OH)2 and HCl is:

Mg(OH)2  +  2HCl  -->  MgCl2  +  2H2O

So we see that for every 2 moles of HCl, 1 mole of Mg is reacted.

Calculating for moles HCl:

moles HCl = 0.300 M * 0.215 L

moles HCl = 0.0645 mol

The moles Mg then is:

moles Mg = 0.0645 mol * (1 / 2)

moles Mg = 0.03225 mol

0.03255 moles of Mg is used for neutralizing 0.3 M 245 ml .

The chemical reaction of the reaction of Mg with water yields Magnesium hydroxide.

The neutralization reaction of with HCl will be:

For neutralizing 1 mole of magnesium hydroxide 2 moles of HCl are required.

The moles  of HCl in the question are:

moles =

moles of HCl = 0.3

moles of HCl = 0.0645 moles.

The moles of Mg required are half of HCl.

Moles of Mg =

Moles of Mg = 0.03225.

0.03255 moles of Mg is used for neutralizing 0.3 M 245 ml .

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it is called acid bonding

it would be b. 6co2 + 6h2o --> c6h12o6 + 6o2