Question

How many moles of $A{l}^{3+}$ are present in 300mL of 0.2 N $A{l}_2{\left(S{O}_4\right)}_3$?

• A. $2\times {10}^{-2}$
• B. $1\times {10}^{-3}$
• C. $1\times {10}^{-2}$
• D. $1\times {10}^{-4}$

Answer 1

Answer: (A)

$2\times {10}^{-2}$

$n_{factor}$ of $Al=3$ (Valency)

$Numberofmoles=\frac{Normality\times Volume}{n_{factor}}=\frac{0.2\times 300}{3}=20$ $millimoles=2\times {10}^{-2}$ $moles$