Nalorphene `(C_(19)H_(21)NO_3)` 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 xx 10^(-3)m` aqueous solution required for the above dose is

Options

A. 4.2 g
B. 3.2 g
C. 2.2 g
D. 1.2 g

Answer

B

Explanation

`w_B=1.5 xx 10^(-3) g, m_B=19xx12+21+14+16xx 3=311`,
`m=(w_B//m_B)/M_A xx 1000 = 1.5 xx 10^(-3)m, M_A = ?`
`1.5 xx10^(-3)= (1.5xx10^(-3)//311)/M_A xx 100`
`M_A=(1.5xx10^(-3))/(311 xx1.5xx10^(-3))xx1000 = 1000/311 = 3.2 g`