Research Paper on Examining the Reaction of Acid-Base

Introduction

The aim of this experiment was examining the reaction of acid-base through observation of the way acid is dissolved when it hits the water to neutralize.

Is your time best spent reading someone else’s essay? Get a 100% original essay FROM A CERTIFIED WRITER!

Save 25%

Materials

Alka-Seltzer, one tablet Vinegar, CH3CO2H, 10 mL, Sodium hydroxide, NaOH, 0.1 M, 100 mL, Beaker, 600-mL, Universal indicator, 10 mL, Graduated cylinders; 500-mL, 100-mL, and 10-ml water distilled, 350 mL and Stirring rod

Methods

1. Measure out approximately 350 mL of distilled water in a 600-mL beaker.

2. Add 100 mL of 0.1 M sodium hydroxide solution.

3. Add 10 mL of the universal indicator solution and stir. The solution should now be dark purple.

4. Pour the solution into a 500-mL graduated cylinder.

5. Use a clean graduated cylinder to measure out 10 mL of vinegar

Procedure

1. Drop an Alka-Seltzer tablet into the 500-mL graduated cylinder. Color changes should begin to occur as soon as the first carbon dioxide bubbles are formed.

2. When the tablet rises to the top, add about 10 mL of vinegar to the solution. The solution should now be red on the top.

Discussion

DARK PURPLE DARK BLUE GREEN YELLOW ORANGE REP Beaker

Equations: HCO3- (aq) + H+(aq) H2CO3(aq)

Equation 2: H2CO3 H2O(aq)+CO2(g)Equation 3: H2CO3(aq) + OH- (ag) CO2(g) + H2O(L)Equation 4: H2CO3-(aq) + OH- (ag) CO32-(g) + H2O(L)The Alka-Seltzer tablet contains sodium bicarbonate and citric acid, hence when the tablet is dissolving the sodium bicarbonate is reacting with citric acid to form carbonic acid which is expressed in equation 1. The solution changes color because the carbonic acid being created by the tablet reacts with the basic solution in the beaker. Carbonic acid reacts with sodium hydroxide that results to a reduction on the PH levels of the solution. The solution gradually becomes acidic that results in color.

As Alka-Seltzer tablets dissolve in water, carbon dioxide is produced evidenced by the bubbles. The reaction resembles the production of carbon dioxide where sodium bicarbonate is mixed with an acid (Alka-Seltzer tablets) that had initially sunk at the cylinder bottom begins to rise to the top because of the bubbles forming under it pushes it up. When CO2 adhere to the surface of the tablets, its surface area increases that result to it rising to the top of the cylinder. The addition of vinegar to the solution which is weak acid results to a pH gradient. Moreover, the buoyancy of the tablets exposes them to reaction with vinegar. The universal indicator added to the solution results in a shift in the pH gradient visible and produced a characteristic rainbow color.

The universal indicator changes colors to indicate the pH levels of the solution. While mixing vinegar which is an acid solution with sodium carbonate which is a basic solution, the effect of the indicator was a spectrum. The fluid density principle was key to resulting in the rainbow effect. The sodium carbonate solution is denser than the indicator. Hence it went down at the bottom of the beaker. While sodium carbonate was sinking, a number of its molecules mixed with vinegar resulting in a new solution that displays as a color pH the pH scale.

Conclusion

The primary purpose of the experiment was to examine the reaction when acid hits the water to neutralize. The solution formed when sodium bicarbonate reacted with citric acid, the color changed. The pH reduction was a result of the reaction between carbonic acid and sodium hydroxide. CO2 produced increased the buoyancy of the tablets that resulted increased its surface area for reaction. Universal indicator added to the solution results in a shift in the pH gradient visible and produced a characteristic rainbow color.