How to calculate the pH of the solution if 150 mL of hydrochloric acid is consumed to complete the raction with the magnesium, with a total concentration of 0.45 #"mol / dm"^-3#?

Question

#MgO(s ) + 2HCl(aq ) -> MgCl_2(aq ) + H_2O( l) #

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Answer 1 · 2017-12-29T17:31:27

Well, at equivalence the solution is stoichiometric in #MgCl_2(aq)#...

And thus #pH# should be near as dammit to #7#.

It is likely that the question asks as to the MASS of magnesium oxide that was decomposed by the acid....

And you have provided the stoichiometric equation...

#MgO(s) + 2HCl(aq) rarr MgCl_2(aq)+H_2O(l)#

Now with respect to hydrochloric we used a molar quantity of...

#150*mLxx10^-3*L*mL^-1xx0.45*dm^3xx1*L*dm^-3#

#=0.0675*mol#.

And so WITH RESPECT TO magnesium oxide, there was a mass of...

#0.0675*molxx1/2xx40.30*g=1.36*g#.

If I am barking up the wrong tree, I apologize....