Lea has just ordered a box of "universal" litmus paper. She dips one piece into vial A, and it turns green. She dips another piece into vial B, and it turns red. A pack of papers papers is shown with a scale 1 red, 2 orange-red, 3 orange, 4 pale orange, 5 more pale orange, 6 yellow, 7 yellow green, 8 green, 9 darker green, 10 very dark green, 11 blue, 12 dark blue, 13 purple, 14 dark purple. Which vial, A or B, contains a greater concentration of H+ ions? vial