Question

What is the mass of the precipitate formed when $50 \,mL$ of $16.9 \%$ solution of $AgNO _3$ is mixed with $50 \,mL$ of $5.8 \% NaCl$ solution ?
$( Ag =107.8, N =14, O =16, Na =23, Cl =35.5)$

• A. 7 g
• B. 14 g
• C. 28 g
• D. 3.5 g

Answer 1

Answer: (A)

$16 \cdot 9\, g\, AgNO _3$ is present in $100\, mL$ solution.
$\therefore 8.45 \,g\, AgNO _3$ is present in $50\, mL$ solution
$5.8 \,g\, NaCl$ is present in $100\, mL$ solution
$\therefore 2.9\, g \,NaCl$ is present in $50\, mL$ solution
$AgNO _3+ NaCl \longrightarrow AgCl + NaNO _3$
$\frac{8 \cdot 45}{170} mol \frac{2.9}{58.5}$
$=0 \cdot 049 mol =0 \cdot 049 mol \rightarrow 00$
after
reaction00 $\rightarrow 0 \cdot 049 mol 0 \cdot 049 mol$ mass of $AgCl$ precipitated
$=0.049 \times 143.5\, g$
$=7\, g \,Ag Cl$