A 125 mL sample of phosphoric acid was titrated with an average of 63.7 mL of a 0.050M barium hydroxide solution according to the given reaction: 2 H3PO4 + 3 Ba(OH)2 ⇌ Ba3(PO4)2 + 6 H2O Determine the concentration of the phosphoric acid sample:

0.017 M

Explanation:

The balanced equation for the reaction is given below:

2H₃PO₄ + 3Ba(OH)₂ ⇌ Ba₃(PO₄)₂ + 6H₂O

From the balanced equation above,

The mole ratio of acid, H₃PO₄ (nₐ) = 2

The mole ratio of base, Ba(OH)₂ (n₆) = 3

Finally, we shall determine the concentration of the phosphoric acid, H₃PO₄. This can be obtained as follow:

Volume of acid, H₃PO₄ (Vₐ) = 125 mL

Volume of base, Ba(OH)₂ (V₆) = 63.7 mL

Concentration of base, Ba(OH)₂ (C₆) = 0.050M

Concentration of acid, H₃PO₄ (Cₐ) =?

CₐVₐ / C₆V₆ = nₐ/n₆

Cₐ × 125 / 0.05 × 63.7 = 2/3

Cₐ × 125 / 3.185 = 2/3

Cross multiply

Cₐ × 125 × 3 = 3.185 × 2

Cₐ × 375 = 6.37

Divide both side by 375

Cₐ = 6.37 / 375

Cₐ = 0.017 M

Thus, the concentration of the phosphoric acid, H₃PO₄ is 0.017 M

most historians agree that gabriel mouton, the vicar of st. paul’s church in lyons, france, is the “founding father” of the metric system. he proposed a decimal system of measurement in 1670. mouton based it on the length of one minute of arc of a great circle of the earth (now called a nautical mile, 1852 meters). he also proposed the swing-length of a pendulum with a frequency of one beat per second as the unit of length (about 25 cm). a pendulum beating with this length would have been fairly easy to produce, thus facilitating the widespread distribution of uniform standards. over the years, his work was revised, improved, and extended by a number of french scientists.

the political sponsor of weights and measures reform in the french revolutionary national assembly was the bishop of autun, better known as talleyrand. under his auspices, the french academy appointed several committees to carry out the work of developing a usable system of weights and measures for france. one of the committees recommended a decimalized measurement system based upon a length equal to one ten-millionth of the length of a quadrant of the earth’s meridian (i.e., one ten-millionth of the distance between the equator and the north pole).