Respuesta :
Answer: The number of valence electrons that M must have is 1.
Explanation:
The chemical equation for the reaction of metal oxide with water follows:
[tex]\text{Metal oxide}+H_2O\rightarrow M(OH)_x[/tex]
The reaction of metal hydroxide with hydrochloric acid follows:
[tex]M(OH)_x+xHCl\rightarrow MCl_x+xH_2O[/tex]
To calculate the number of moles for given molarity, we use the equation:
[tex]\text{Molarity of the solution}=\frac{\text{Moles of solute}\times 1000}{\text{Volume of solution (in mL)}}[/tex] .....(1)
- For metal hydroxide:
Molarity of metal hydroxide solution = 0.40 M
Volume of solution = 75 mL
Putting values in equation 1, we get:
[tex]0.40=\frac{\text{Moles of }M(OH)_x\times 1000}{75}\\\\\text{Moles of }M(OH)_x=\frac{0.40\times 75}{1000}=0.03mol[/tex]
- For HCl:
Molarity of HCl = 1.1 M
Volume of solution = 27 mL
Putting values in equation 1, we get:
[tex]1.1=\frac{\text{Moles of HCl}\times 1000}{27}\\\\\text{Moles of HCl}=\frac{1.1\times 27}{1000}=0.0297mol[/tex]
To calculate the value of 'x', we divide the number of moles of HCl by number of moles of metal hydroxide, we get:
[tex]x=\frac{\text{Moles of HCl}}{\text{Moles of }M(OH)_x}\\\\x=\frac{0.0297}{0.03}=0.99\approx 1[/tex]
Hence, the number of valence electrons that M must have is 1.
