Analysis of neutralizing power of anti-acid tablets

Authors Avatar

Analysis of neutralizing power of anti-acid tablets

By: 6A Ting Ting Chang (1)

   Katie Cheung (2)

    Winnie Yeung (27)

Chemical Principles:

Neutralization occurs when acid and alkali are mixed together. It involves the reaction between H+ and OH-, forming salt and water. The properties of acid and alkali will be cancelled out in the process of neutralization.

In our stomach, the gastric juice inside contains concentrated HCl (at about pH2). When excessive amount of gastric juice is secreted, we will feel discomfort in stomach or even heartburn. In this case, anti-acid tablets can be used to relief the pain. The suspension of the anti-acid contain OH- which will combine with the H+ found in the HCl of the juice to form a salt and water. Thus, the excess gastric juice can be neutralized.

In this experiment, the active ingredient contents (Mg(OH)2 / Al(OH)3) of different brands of anti-acids are analyzed using volumetric analysis. Since Mg(OH)2 / Al(OH)3 is insoluble in water, we cannot determine the actual amount of OH- by simply titrating its aqueous solution against HCl(aq). Thus, we should first dissolve it in excess amount of HCl(aq) of known molarity. Then, we should carry out back titration of the reaction mixture against NaOH of known molarity, in order to determine the amount of H+ left in the reaction mixture. In this way, we can find out the actual amount of H+ used to neutralize the OH- inside the tablets. At last, we can determine the amount of active ingredients inside the anti-acid tablets.

Join now!

Reactions involved:

Mg(OH)2(s) + 2HCl(aq)     MgCl2(aq) +2H2O(l)

Al(OH)3(s) +3HCl(aq)     AlCl3(aq) +3H2O(l)

NaOH(aq) +HCl(aq)      NaCl(aq) + H2O(l)

Brands we have chosen:

  1. ACTAL plus anti-acid tablet

Contents:         Aluminium Hydroxide 200mg

                                Magnesium Hydroxide 150mg

                                Simethicone* 25mg

  1. Hydrosil Tab

Contents:         Aluminium Hydroxide 200mg

                                Magnesium Hydroxide 200mg

                                Simethicone 20mg

  1. Maalox Plus Tab

Contents:         Aluminium Hydroxide 200mg

                                Magnesium Hydroxide 200mg

                                Simethicone 25mg

  1. Magsil

Contents:                Aluminium Hydroxide Dried Gel 200mg

                                Magnesium Hydroxide 200mg

                                

  1. Fedra-Gel-S

Contents:                Aluminium Hydroxide Dried Gel 200mg

                                Magnesium Hydroxide 200mg

                                Simethicone 30mg

* Simethicone is an anti-foaming agent that decreases the surface ...

This is a preview of the whole essay