Init: 5/25/2011 by Daniel R. Barnes

1.H 2 O 2. H 2 SO 4 3.NaCl 4.NaOH 5.HCl 6.NaHCO 3 Our Samples: 7.NaClO 8.NH 3 9.CH 3 COOH 10. CH 3 CHOHCH C 12 H 22 O CuSO 4

Your liquid indicator in this lab is... phenolphthalein

This is a drop plate. It has twelve wells in it. well

pH paper blue litmus paper red litmus paper The color code chart in the pH paper container applies only to the pH paper. It does NOT apply to the litmus paper. pH paper Color code chart

Please do the lab before proceeding any further. Thank you.

1. H 2 O acidbase water Hydrogen hydroxide Hydronium hydroxide

“STRONG” dissociation 2. H 2 SO 4 sulfuric acid “weak” dissociation H 2 SO 4 + H 2 O  H 3 O + + HSO 4 - HSO H 2 O  H 3 O + + SO 4 2- strong acid weak acid

3. NaCl sodium chloride NaCl(cr)  Na + (aq) + Cl - (aq) “table salt”

4. NaOH sodium hydroxide NaOH(cr)  Na + (aq) + OH - (aq) “lye” base

5. HCl hydrogen chloride HCl(g) + H 2 O(l)  H 3 O + (aq) + Cl - (aq) hydrochloric acid acid

6. NaHCO 3 sodium hydrogen carbonate sodium bicarbonate baking soda NaHCO 3 (cr)  Na + (aq) + HCO 3 - (aq) HCO 3 - (aq) + H 3 O + (aq)  H 2 CO 3 (aq) + H 2 O(l) base

7. NaClO sodium hypochlorite bleach says the pH of bleach is 12.6 NaClO(cr)  Na + (aq) + ClO - (aq) ClO - (aq) + H 3 O + (aq)  HClO(aq) + H 2 O(l) base H2OH2O

Cl 2 = Cl - = ClO - = ClO 2 - = ClO 3 - = ClO 4 - = “chlorine” “chloride” “chlorate” “chlorite” “hypochlorite” “perchlorate” The hypochlorite ion found in liquid chlorine bleach is just one of a series of chlorine- containing species.

8. NH 3 ammonia ammonium hydroxide NH 3 (g) + H 2 O(l)  NH 4 + (aq) + OH - (aq) base

9. CH 3 COOH acetic acid ethanoic acid vinegar CH 3 COOH(aq) + H 2 O(l)  H 3 O + (aq) + CH 3 COO - (aq) acid

10. CH 3 CHOHCH 3 isopropanol isopropyl alcohol rubbing alcohol C C C H H H H H H H The OH in an alcohol molecule doesn’t come off in water. base?

11. C 12 H 22 O 11 sucrose table sugar The OH in a sugar doesn’t come off in water. base?

12. CuSO 4 copper sulfate CuSO 4  Cu 2+ (aq) + SO 4 2- (aq) Cu 2+ (aq) + 2OH - (aq)  Cu(OH) 2 (cr) acid SO 4 2- (aq) + H 3 O + (aq)  HSO 4 - (aq) + H 2 O(l) base A 0.2M solution is said to have a pH of 4.

1. What is the relationship between the pH of a sample and its effect upon the two colors of litmus paper? CONCLUSIONS: “Blue litmus paper turns red under acidic conditions and red litmus paper turns blue under basic (i.e. alkaline) conditions, with the color change occurring over the pH range at 25 °C. Neutral litmus paper is purple.” Your results may not be exactly the same as everyone else’s, so you have to answer the question based on your data. However, here’s what wikipedia says: That’s not quite as simple as what I was brought up to believe, but what we are taught in school is often an over-simplification of reality.

Blue (top) and red (bottom) litmus paper. When litmus paper is placed in acid, the red stays red (bottom right) and the blue turns red (top right). When litmus paper is placed in base, the blue stays blue (top left) and the red turns blue (bottom left).

CONCLUSIONS: 2. What liquid indicator did you use? What is the relationship between the pH of a sample and the color it turned when the liquid indicator was mixed with it? If the pH was less than or equal to 7, the phenolphthalein remained clear. If the pH was greater than 7, the phenolphthalein turned hot pink (fuchsia/magenta). We used phenolphthalein as our liquid indicator in this lab. Click me to remove me Click me to remove me Click me to remove me Click me to remove me