Question

Number of ions present in $1$ ml of $0.1$ M barium nitrate solution is:

• A. $1.8\times$ ${10}^{20}$
• B. $6\times$ ${10}^{19}$
• C. $1.8\times$ ${10}^{23}$
• D. $1.8\times$ ${10}^{-20}$

Answer 1

The correct option is A $1.8\times$ ${10}^{20}$

$1$ ml of $0.1$ M barium nitrate solution corresponds to $0.001\times 0.1=0.0001$ moles.

$Ba{\left(N{O}_3\right)}_2⟶B{a}^{2+}+{2N{O}_3}^{-}$

$1$ molecule of barium nitrate $Ba(N{O}_3{)}_2$ will give $3$ ions.

Hence, the number of ions present in $1$ ml of $0.1$ M $Ba(N{O}_3{)}_2$ solution $=0.0001\times 3\times 6.02\times {10}^{23}$

$=1.8\times {10}^{20}$.