State an equation to represent a neutralization reaction with one of the above antacids.

State and explain whether 0.1 mol of magnesium hydroxide is more effective or less effective than 0.1 mol of aluminium hydroxide.

Suggest why compounds such as sodium hydroxide or potassium hydroxide cannot be used as an antacid.

\({\text{Al(OH}}{{\text{)}}_3} + {\text{3HCl}} \to {\text{AlC}}{{\text{l}}_3} + {\text{3}}{{\text{H}}_2}{\text{O}}/{\text{Mg(OH}}{{\text{)}}_2} + {\text{2HCl}} \to {\text{MgC}}{{\text{l}}_2} + {\text{2}}{{\text{H}}_2}{\text{O}}\);

Accept ionic equations.

less effective and (magnesium hydroxide) 2/0.2 mol \({\text{O}}{{\text{H}}^ - }\) ions available as compared to (aluminium hydroxide) 3/0.3 mol OH– ions for neutralization / neutralizes \({\text{2}}{{\text{H}}^ + }\)/0.2 mol acid as compared to \({\text{3}}{{\text{H}}^ + }\)/0.3 mol acid; [1]

Do not accept aluminium hydroxide can neutralize more acid.

strong base / corrosive / harmful to the body;

Whilst quite a few candidates could write one of the required balanced equations a surprising large number could not succeed in this simple task. Answers to the second part of this question often lacked the stoichiometric rigour required and the reasons for not using strong alkalis provoked an amazing range of responses, mostly incorrect and many exposing a worrying lack of basic chemical knowledge. Only a minority of the students could correctly identify the function of alginates and dimethicone in antacid preparations.

Whilst quite a few candidates could write one of the required balanced equations a surprising large number could not succeed in this simple task. Answers to the second part of this question often lacked the stoichiometric rigour required and the reasons for not using strong alkalis provoked an amazing range of responses, mostly incorrect and many exposing a worrying lack of basic chemical knowledge. Only a minority of the students could correctly identify the function of alginates and dimethicone in antacid preparations.

Whilst quite a few candidates could write one of the required balanced equations a surprising large number could not succeed in this simple task. Answers to the second part of this question often lacked the stoichiometric rigour required and the reasons for not using strong alkalis provoked an amazing range of responses, mostly incorrect and many exposing a worrying lack of basic chemical knowledge. Only a minority of the students could correctly identify the function of alginates and dimethicone in antacid preparations.