Question

Acid, bases and buffers

Acids, Bases, and Buffers CHEM& 121 Lab Partner Data Part A Red pH Red Cabbage Test Tube Blue Litmus (color) Solution Juice (color)values (colbr) no reaction 2.890 Magenta 11.37dark green Red blue no reaction 2.700 Magenta lemon juice soft drink drain cleaner no reaction detergent baking soda no reaction red red no raction 3.530 Purple blue 12.56 no reactionno reaction 8.700 dark green 9.350 teal/green Part B Total Number of rops of HCl(aq) Added DI Water ColorPH Buffered Solution Color yellow tint yellow tint yellow tint pH 7.300 5.370 3.580 3.280 3.060 light yellow7.190 3.020 light yellow 2.910almost clear 7.070 clear 7.230 clear clear clear clear 7.150 Total Number of Drops of NaOH(aq) Added DI Water Buffered Solution Color clear pink dark pink purple pink purple pink light pink Color S.340 10.50 11.40 11.31 1149 11.64 clear 7.340 7.410 7.380 7 380 7.380 clear Part A 1. Which of the household solutions tested are acids? How can you tel? 2. Which of the solutions are bases? How can you tel? 3. What color(s is red cabbage juice indicator in acids? in bases? 4 State at least one advantage and disadvantage for each of the following methods for determining pH Advantages? Disadvantages? Ltmus Paper Red Cabbage Juice pH probe Part B . Briefy explan any dfferences observed for Di wiater compared to a buffered soution when HCi (aq) was added to each. Part B Briefly explain any differences observed for DI water compared to a buffered solution when HCI (aq) was added to each. Briefly explain any differences observed for Di water compared to a buffered solution when NaOH (aq) was added to each . a. What is the observed pH range for the color change you observed in Part B? b. Does this mean that the indicator (phenolphthalein) changes color in acidic or basic solution? Consider a buffer solution that consists of the weak acid. HF(aq), and its conjugate base, Fa . Write the reaction that occurs when a strong acid (H- or H0-) is added to the buffered solution wrte the reacton that occurs when a strong base (oH) is added to the buffered solution.

Answer 1

Part A:- blue litmus changes to red- acid

Red litmus changes to blue- Base

Red cabbage juice gives magneta colour- in acid

red cabbage juice gives bluish green colour in Base.

1. Vinegar, lemon juice, soft drink are acidic. This is indicated by the litmus paper which turns blue to red and also by the red cabbage juice which turns to magneta colour and it's ph also indicates that these are acidic in nature

2. Ammonia, drain cleaner and baking soda are basic in nature. This is indicated by the blue litmus and red cabbage juice and by pH also.

3. Red cabbage gives reddish pink colour in acidic media and gives greenish blue colour in basic media.