Question

Nalorphene $\left( C _{19} H _{21} NO _{3}\right)$ similar to morphine, is used to combat withdrawal symptoms in narcotic uses. Dose of nalorphene generally given is $1.5\, mg$. The mass of $1.5 \times 10^{-3} m$ aqueous solution required for the above dose is?

• A. 5.2 g
• B. 3.2 g
• C. 4.6 g
• D. 1.9 g

Answer 1

Answer: (B)

$w _{ B }=1.5 \times 10^{-3} g$
$M _{ B }=19 \times 12+21 \times 1+14+3 \times 16=311$
We know
$m =\frac{ w _{ B } / M _{ B }}{ w _{ A }} \times 1000$
$1.5 \times 10^{-3}=\frac{1.5 \times 10^{-3} / 311}{w_{A}} \times 1000$
$w_{A}=\frac{1.5 \times 10^{-3}}{311 \times 1.5 \times 10^{-3}} \times 1000$
$=\frac{1000}{311}=3.2\, g .$