Question

Tungsten trioxide (W0z) has a rich yellow color and is often used as a pigment in ceramics and paints. To test a ceramic vase for its Wo, content, a 10.23 g sample of the vase was ground and reduced with Pb(Hg) to convert any Wo, to W3+. The resulting W3+ was transferred to 500.0 mL of 1.00 M HCl. A 100.00 mL aliquot of the HCl solution required 14.42 mL of 0.09337 M potassium permanganate (KMnO2) to reach the purple endpoint. A blank required 0.19 mL. Balance the redox reaction. redox reaction: MnO2 + W3+ Mn2+ + woz+ Determine the percent Wo, in the ceramic sample. percent WOz:

Answer 1

solution: Givendata, Tugsten trioxide (w03) has a rich yellow color and is often used as a pigment in ceramics and paints. To test a ceramic vase for its woz content a 10.239. - transfered to 500.0mL of 1.00m Hd. 7 solution required 14.42 mL of O. 09337 m & potassium permaganate (Im nou). A blank required 0.19 m2 redox reachion is mnou t wit mnat + wort The balanced redox reaction is, .. 3mout 5w3t tuht 3mnt +5w0t + 2H₂O - moles of mnou = (volume - blank volume) x concentration of by substituting we get .. = (14.42 -0.19) * 0.09337m 14.23 X 0.09337 moles of mnou = 1.3286 molt

molar of 103t in 100m aliquat - 5 t molar of mnou = I x 1.3286 mol Imolar or wat in lomla 2.21 uuu mol. 1 arluat molar of wo3 = molar Of wat in 500 ml aliquet = 500 x 2.20 U u mol 100_ Imolar of wo3 - 11.0.721 mol mass of Woz e molar y molar mass of 203 11:0721 x 231.84 mol armas Of Woz 9,566.9626 mol Imass of wo3 = 22 566 9117 mass of of wo3 = X 100 mass of sample by substituting we geti. mass Of WO3 2.566 2.566 x 100 10.23 = 100 250.922 X 100 2540922 % 25.0922 mass t. of wo2 = 25-09227.7