{"id":163,"date":"2025-05-29T02:13:18","date_gmt":"2025-05-29T02:13:18","guid":{"rendered":"https:\/\/pressbooks.hccfl.edu\/introchemlabmanual\/?post_type=chapter&#038;p=163"},"modified":"2026-03-24T16:57:50","modified_gmt":"2026-03-24T16:57:50","slug":"procedure","status":"web-only","type":"chapter","link":"https:\/\/pressbooks.hccfl.edu\/introchemlabmanual\/chapter\/procedure\/","title":{"raw":"Laboratory Preparation &amp; Procedure","rendered":"Laboratory Preparation &amp; Procedure"},"content":{"raw":"<h2>Materials:<\/h2>\r\n<ul>\r\n \t<li>Solid Potassium Hydrogen Phthalate (KHP)<\/li>\r\n \t<li>Sodium hydroxide solution (unknown concentration)<\/li>\r\n \t<li>deionized water<\/li>\r\n \t<li>phenolphthalein indicator<\/li>\r\n \t<li>burette<\/li>\r\n \t<li>burette clamp<\/li>\r\n \t<li>ring stand<\/li>\r\n \t<li>stir plate<\/li>\r\n \t<li>magnetic stir bar<\/li>\r\n \t<li>250 mL Erlenmeyer flask<\/li>\r\n \t<li>100 mL beaker<\/li>\r\n \t<li>funnel<\/li>\r\n \t<li>analytical balance<\/li>\r\n \t<li>weigh tray<\/li>\r\n<\/ul>\r\n<h2>Safety:<\/h2>\r\nNaOH is corrosive. Wear gloves at all times.\r\n<h2>Procedure:<\/h2>\r\nClean and dry a weighing boat.\r\n\r\n2. Place the container on the analytical balance and tare (zero) it.\r\n\r\n3. Accurately weigh between 0.6 to 0.8 g of solid KHP. Record each exact mass as shown on the balance.\r\n\r\n4. Transfer the KHP sample into a 250-mL Erlenmeyer flask.\r\n\r\n5. Add about 25\u201350 mL of deionized water to the flask. Add a magnetic stir bar and swirl on the stir plate until the KHP is fully dissolved.\r\n\r\n6. Add 2\u20133 drops of phenolphthalein indicator to the flask.\r\n\r\n7. Setup your burette, ring stand, and stir plate as shown in the figure below. Secure the burette vertically to a ring stand using a burette clamp.\r\n\r\n[caption id=\"attachment_171\" align=\"aligncenter\" width=\"192\"]<img class=\"wp-image-171\" src=\"http:\/\/pressbooks.hccfl.edu\/introchemlabmanual\/wp-content\/uploads\/sites\/99\/2025\/05\/Titration-Setup-200x300.png\" alt=\"Titration setup with a ring stand and burette hovered over a magnetic stir plate.\" width=\"192\" height=\"288\" \/> Image generated by OpenAI\u2019s DALL\u00b7E.[\/caption]\r\n\r\n8. Using a funnel, rinse the burette with 10-mL deionized water. Discard the rinse into a waste beaker.\r\n\r\n9. Condition your burette by running 5 mL of the NaOH solution through the burette Discard the rinse into a waste beaker.\r\n\r\n10. Rinse the burette a second time with a fresh sample of 5 mL of the NaOH solution. Discard the rinse into a waste beaker.\r\n\r\n11. Close the stopcock &amp; use a funnel to fill the burette with the NaOH solution to just above the 0.00 mL mark.\r\n\r\n12. Remove the funnel after filling to prevent additional drops from entering.\r\n\r\n13. Open the stopcock briefly to remove air bubbles from the tip and bring the level down to just at or below 0.00 mL.\r\n\r\n14. Record the initial volume of NaOH to the correct precision of the instrument.\r\n\r\n15. Place the Erlenmeyer flask containing the dissolved KHP under the burette on a white background (like paper) to help detect the endpoint color change.\r\n\r\n16. Slowly add NaOH while gently swirling the flask with your other hand.\r\n\r\n17. As the pink color begins to persist faintly, reduce the flow rate to dropwise.\r\n\r\n18. Stop adding NaOH when the pale pink color remains for at least 30 seconds. This is the endpoint of the titration. A dark pink color indicates you have over titrated your sample and have passed the endpoint.\r\n\r\n19. Record the final volume of NaOH from the burette to the correct precision of the instrument.\r\n\r\n20. Repeat steps 15\u201319 for at least two additional KHP samples, ensuring consistent swirling and endpoint detection.\r\n\r\n21. Rinse all glassware with deionized water.\r\n\r\n22. Dispose of waste solutions as directed by your instructor.","rendered":"<h2>Materials:<\/h2>\n<ul>\n<li>Solid Potassium Hydrogen Phthalate (KHP)<\/li>\n<li>Sodium hydroxide solution (unknown concentration)<\/li>\n<li>deionized water<\/li>\n<li>phenolphthalein indicator<\/li>\n<li>burette<\/li>\n<li>burette clamp<\/li>\n<li>ring stand<\/li>\n<li>stir plate<\/li>\n<li>magnetic stir bar<\/li>\n<li>250 mL Erlenmeyer flask<\/li>\n<li>100 mL beaker<\/li>\n<li>funnel<\/li>\n<li>analytical balance<\/li>\n<li>weigh tray<\/li>\n<\/ul>\n<h2>Safety:<\/h2>\n<p>NaOH is corrosive. Wear gloves at all times.<\/p>\n<h2>Procedure:<\/h2>\n<p>Clean and dry a weighing boat.<\/p>\n<p>2. Place the container on the analytical balance and tare (zero) it.<\/p>\n<p>3. Accurately weigh between 0.6 to 0.8 g of solid KHP. Record each exact mass as shown on the balance.<\/p>\n<p>4. Transfer the KHP sample into a 250-mL Erlenmeyer flask.<\/p>\n<p>5. Add about 25\u201350 mL of deionized water to the flask. Add a magnetic stir bar and swirl on the stir plate until the KHP is fully dissolved.<\/p>\n<p>6. Add 2\u20133 drops of phenolphthalein indicator to the flask.<\/p>\n<p>7. Setup your burette, ring stand, and stir plate as shown in the figure below. Secure the burette vertically to a ring stand using a burette clamp.<\/p>\n<figure id=\"attachment_171\" aria-describedby=\"caption-attachment-171\" style=\"width: 192px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-171\" src=\"http:\/\/pressbooks.hccfl.edu\/introchemlabmanual\/wp-content\/uploads\/sites\/99\/2025\/05\/Titration-Setup-200x300.png\" alt=\"Titration setup with a ring stand and burette hovered over a magnetic stir plate.\" width=\"192\" height=\"288\" srcset=\"https:\/\/pressbooks.hccfl.edu\/introchemlabmanual\/wp-content\/uploads\/sites\/99\/2025\/05\/Titration-Setup-200x300.png 200w, https:\/\/pressbooks.hccfl.edu\/introchemlabmanual\/wp-content\/uploads\/sites\/99\/2025\/05\/Titration-Setup.png 1024w\" sizes=\"auto, (max-width: 192px) 100vw, 192px\" \/><figcaption id=\"caption-attachment-171\" class=\"wp-caption-text\">Image generated by OpenAI\u2019s DALL\u00b7E.<\/figcaption><\/figure>\n<p>8. Using a funnel, rinse the burette with 10-mL deionized water. Discard the rinse into a waste beaker.<\/p>\n<p>9. Condition your burette by running 5 mL of the NaOH solution through the burette Discard the rinse into a waste beaker.<\/p>\n<p>10. Rinse the burette a second time with a fresh sample of 5 mL of the NaOH solution. Discard the rinse into a waste beaker.<\/p>\n<p>11. Close the stopcock &amp; use a funnel to fill the burette with the NaOH solution to just above the 0.00 mL mark.<\/p>\n<p>12. Remove the funnel after filling to prevent additional drops from entering.<\/p>\n<p>13. Open the stopcock briefly to remove air bubbles from the tip and bring the level down to just at or below 0.00 mL.<\/p>\n<p>14. Record the initial volume of NaOH to the correct precision of the instrument.<\/p>\n<p>15. Place the Erlenmeyer flask containing the dissolved KHP under the burette on a white background (like paper) to help detect the endpoint color change.<\/p>\n<p>16. Slowly add NaOH while gently swirling the flask with your other hand.<\/p>\n<p>17. As the pink color begins to persist faintly, reduce the flow rate to dropwise.<\/p>\n<p>18. Stop adding NaOH when the pale pink color remains for at least 30 seconds. This is the endpoint of the titration. A dark pink color indicates you have over titrated your sample and have passed the endpoint.<\/p>\n<p>19. Record the final volume of NaOH from the burette to the correct precision of the instrument.<\/p>\n<p>20. Repeat steps 15\u201319 for at least two additional KHP samples, ensuring consistent swirling and endpoint detection.<\/p>\n<p>21. Rinse all glassware with deionized water.<\/p>\n<p>22. Dispose of waste solutions as directed by your instructor.<\/p>\n","protected":false},"author":125,"menu_order":2,"template":"","meta":{"pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"class_list":["post-163","chapter","type-chapter","status-web-only","hentry"],"part":144,"_links":{"self":[{"href":"https:\/\/pressbooks.hccfl.edu\/introchemlabmanual\/wp-json\/pressbooks\/v2\/chapters\/163","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pressbooks.hccfl.edu\/introchemlabmanual\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/pressbooks.hccfl.edu\/introchemlabmanual\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/pressbooks.hccfl.edu\/introchemlabmanual\/wp-json\/wp\/v2\/users\/125"}],"version-history":[{"count":13,"href":"https:\/\/pressbooks.hccfl.edu\/introchemlabmanual\/wp-json\/pressbooks\/v2\/chapters\/163\/revisions"}],"predecessor-version":[{"id":936,"href":"https:\/\/pressbooks.hccfl.edu\/introchemlabmanual\/wp-json\/pressbooks\/v2\/chapters\/163\/revisions\/936"}],"part":[{"href":"https:\/\/pressbooks.hccfl.edu\/introchemlabmanual\/wp-json\/pressbooks\/v2\/parts\/144"}],"metadata":[{"href":"https:\/\/pressbooks.hccfl.edu\/introchemlabmanual\/wp-json\/pressbooks\/v2\/chapters\/163\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/pressbooks.hccfl.edu\/introchemlabmanual\/wp-json\/wp\/v2\/media?parent=163"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/pressbooks.hccfl.edu\/introchemlabmanual\/wp-json\/pressbooks\/v2\/chapter-type?post=163"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/pressbooks.hccfl.edu\/introchemlabmanual\/wp-json\/wp\/v2\/contributor?post=163"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/pressbooks.hccfl.edu\/introchemlabmanual\/wp-json\/wp\/v2\/license?post=163"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}