GAMSAT Chemistry: Acids And Bases, The Indispensible Topics

Since the dawn of Human civilization we have always wondered – why the lemon tastes ‘sour’. The answer was a mystery to us until the onset of nineteenth century, when chemical science taught us the term ‘acids’ and ‘bases’. In reality, these two words encompass our daily life in each and every sphere, starting with toothpaste in our morning chore till the end of dinner with a digestive pill. Synonymously, ‘acids’ and ‘bases’ are an integral part of Human life cycle. ACER is wise enough to identify this crucial topic in Chemistry and has reasonably included it within the periphery of GAMSAT chemistry syllabus.

GAMSAT Section III or Logical reasoning in Physical and Biological Sciences deals with multiple choice questions following a background passage, based on a case-study or report or sub-topic in Basic Sciences. Chemistry constitutes one of the 3 major divisions of Basic Sciences (the other two are Physics and Biology). Consequently, ‘acids and bases’ gets duly incorporated or entwined in some of those questions. Let us pick up a model question for better understanding.

Question – The extent by which hydrolysis proceeds are expressed as degree of hydrolysis and are defined as fraction of one mole of the salt that is hydrolysed when equilibrium has been attained. The nature of solution also depends upon the extent up to which the salt has been hydrolysed. Degree of hydrolysis of a salt depends upon concentration of salt at a particular temperature and varies inversely. Consequently, nature of the solution whether acidic or alkaline can be determined. pH of the solution of salt of weak acid and strong base or weak base and strong acid depends upon its concentration. So, by varying the concentration of salts their pH could be adjusted.

For strong acid and weak base salt solution, the [H3O+] at equilibrium will be –

It is now crystal-clear to us that without adequate basic concept in ‘Acids and Bases’ we can’t sink our teeth properly into this apparently baffling question. The terms – pH, hydrolysis of salt, etc embroider the chapter of ‘Acids and Bases’ in Physical Chemistry.

As a well-wisher for all the jovial GAMSAT aspirants I tried to extend my analysis on a crucial topic of GAMSAT chemistry, directly to the candidates. I hope my friends will put the much required emphasis on the topic and consolidate into their respective GAMSAT preparation.