Question

5. You find 425 mL of 0.350 M sodium oxalate in the lab, and you want to use it to make a buffer with a pH of 1.50. What mass of oxalic acid (MW = 90.03 g/mol, K = 5.9 x 10-2) is needed to make this buffer? (10 pts.) (You can neglect any volume changes due to the addition of solid oxalic acid.)

Answer 1

Acidic buffers are solutions that have a pH below 7 and contain a weak acid and one of its salts. For example, a mixture of oxalic acid and sodium oxalate act as an acidic buffer solution.
The formula for pn or an acidic bulter t ool modestined and a for oxalic Acid=5.9x102 28. 08. pil-tlog, = 109. (os.axis)s8 1.237 Prz 1.5 MP 260 Elbise 15.1 phopka = log [salt ] [acid] sist siloxo do morretaone) To 515-1ans nag finder store xo nodar faaral 5-1.235 Tog ebul das sto [acid] me zario e im zure bermula re planer och cc No. 22 mile therefo Salt? Peacher's Signatures

(Page No : Date : 1.863 [alt] AL [acid ] Concentration of Sodium oxalatez 0.35m 1.862 0:35 Ellocs [acid] 20 por 035 : 0.19 m Cocit oos 09 m [acid]a Concentration of oxalic Acid 1.86 Concentration of Oxalic Acil No of moles of Oxalic And Volume in L. Volu volumele yasmes 1o.4254 ] I 125ml So, No of moles of oxalic Acid= Volume X Concentration Teacher's Signature

0.125X0.19= 0.08075 moles of oxalic Acid. Molay Mass: 90.039/mol. So, mass of oxalic Acid needed=molar Massx No olmokes - Too3 X o o8o1 7.279