Answer:
The molarity is 6, 25M
Explanation:
A solution molar---> moles of solute ( in this case, magnesium oxide) in 1 L of solution :
0,8L solution-----5 moles solute
1 L solution----x=(1 L solutionx 5 moles solute)/0,8L solution= 6,25 moles solute---> 6,25M
