Question

50 mL of a solution of magnesium hydroxide on titration with a 0.1 M solution of HCl gave a titre value of 70 mL. The molarity of magnesium hydroxide solution is:

• A. 0.07 M
• B. 0.14 M
• C. 0.28 M
• D. 0.35 M

Answer 1

The correct option is A 0.07 M

Let, the molarity of $Mg\left(O{H}_2\right)$ solution be: $x$ M
So, $n_1\times M_1\times V_1=n_2\times M_2\times V_2$
where, $n_1=n-factorofMg(OH{)}_2=2$
$M_1=molarityofMg(OH{)}_2=x$ M
$V_1=volumeofMg(OH{)}_2=50$ mL
$n_2=n-factorofHCl=1$
$M_2=molarityofHCl=0.1M$
$V_2=volumeofHCl=70$ mL
$\therefore 2\times x\times 50=1\times 0.1\times 70$
$\Rightarrow x=\frac{7}{100}=0.07$
$\therefore$The molarity of $Mg\left(O{H}_2\right)$ solution = 0.07 M