Nalorphene `(C_(19)H_(21)NO_(3))`, similar to morphine , is used to combat withdrawal symptoms in narcotic users. The dose of nalorphene generally given is `1.5 mg`. Calculate the mass of solution of `1.5xx10^(-3)m` aqueous solution required for the above dose.

Explanation

`"Molality (m)"=("Mass of solute /molar mass")/("Mass of solvent in kg")`
` m=1.5xx10^(-3)m=1.5xx10^(-3)molkg^(-1)`
`Mass of solute = 19xx12+21xx1+14+3xx16=311 g mol^(-1)`
`(1.5xx10^(-3))=((1.5xx10^(-3)g)xx(311 g mol^(-1)))/("Mass of solvent")`
`"Mass of solvent"=((1.5xx10^(-3)g))/((311 g mol^(-1))xx(1.5xx10^(-3)mol kg^(-1)))=0.0032 kg`