On which graph paper is absorbance plotted against concentration?

On which graph paper is absorbance plotted against concentration?

• A. Linear Graph Paper
• B. Semilogarithmic Paper
• C. Log-Log Paper
• D. Polar Coordinates Paper

Answer: (B)

Beer's law shows absorbance is directly proportional to concentration when path length and molar absorptivity are constant: A = εlc. Because of this direct relationship, plotting absorbance against concentration on ordinary linear graph paper yields a straight line with slope εl (and ideally through the origin). That straight-line behavior makes linear graph paper the natural choice for visualizing how absorbance changes with concentration and for determining concentration from measured absorbance. Using semilogarithmic paper would not produce a straight line here, since A depends linearly on c, not on its logarithm. The other graph types wouldn’t correctly reflect the direct proportionality described by Beer's law.

Beer's law shows absorbance is directly proportional to concentration when path length and molar absorptivity are constant: A = εlc. Because of this direct relationship, plotting absorbance against concentration on ordinary linear graph paper yields a straight line with slope εl (and ideally through the origin). That straight-line behavior makes linear graph paper the natural choice for visualizing how absorbance changes with concentration and for determining concentration from measured absorbance. Using semilogarithmic paper would not produce a straight line here, since A depends linearly on c, not on its logarithm. The other graph types wouldn’t correctly reflect the direct proportionality described by Beer's law.