Question

The molar extinction coefficient of B (MW = 180) is 4 x 103 L mol-' cm-
1. One-liter solution of which
contains 01358 g pharmaceutical
preparation of B, shows an absorbance of 0.411 in al cm quartz cell.
What is the percentage (will/w) of B in the pharmaceutical preparation?
13.6
2912
10.20​

Answer 1

Explanation:

One-liter solution of which contains 01358 g pharmaceutical preparation of B, shows an absorbance of 0.411 in al cm quartz cell.

E = 4 x $10^{-3}$ L/mol cm

Wt. of sample dissolved in 1L = 0.1358g

Absorbance of 1L solution = 0441 at 1cm

A = ECL

C = $\frac{A}{EL}$

C = $\frac{0.441}{4 * 10^{-3} }$

C = 0.11025 x $10^{-3}$

Quantity of compound = conc. x mol wt

                                      = 0.11025 x$10^{-3}$ x 180

                                      = 0.019845 g

(w/w)% = $\frac{0.019845}{0.1358}$

            = 14.6