Acids, Bases, and Salts Flashcards
define acid
a compound which when dissolved in water yields hydronium ions as the only positively charged ions
define bases
a base is a compound which reacts with hydronium ions of an acid to give salt and water only
define alkali
a compound which when dissolved in water yields hydroxyl ions as the only negatively charged ions
classification of acids based on source
- organic: derived from plants (oxalic, tartatic, citric)
- inorganic: derived from minerals (HCl, H2SO4)
classification of acids on basis of molecular composition
- hydracids: contain hydrogen and a non metal other than oxygen
- oxyacids (acids containing hydrogen, another element, and oxygen)
define basicity of acids
the number of hydrogen ions which can be produced per molecule of acids in aqueous solution or the number of hydroxyl ions with which one molecule of an acid combines
why is acetic acid CH3COOH monobasic
it has four hydrogen atoms in it but ionises in aqueous solution to produce one hydrogen ion per molecule of the acid
define acidity of bases
number of hydroxyl ions which can be produced per molecule of the base in aqueous solution or the number of hydrogen ions with which a molecule of a base combines
types of salts formed by tribasic acids
2 acidic, 1 normal
Arrhenius theory
acids are substances which dissociate in aqueous solution to give H+ ions. Strong acids dissociate almost completely, while weak acids dissociate partially
Lowry-Bronsted’s theory
acids are proton donors, bases are proton acceptors
define neutralization
the process due to which H+ ions of an acid react completely or combine with OH- ions of base to give salt and water only
define heat of neutralization
the amount of heat liberated when 1 gram equivalent of an acid or a base is completely neutralised
define indicators
weak organic compounds which change colour in accordance with the pH of the solution
dissociate slightly in solution producing ions and undissociated molecules. colour of ions depends on hydrogen ion concentration or pH of medium
when is conc. of H+ and OH- ions equal
at 10^-7 mol/dm^3 (25 C)
product of two ionic concentrations
10^-14 (at 25C)
define pH
the negative logarithm (to the base 10) of the hydrogen ion concentration expressed in moles/litre
define salt
a compound formed by partial or complete replacement of the replaceable (ionizable) hydrogen ion of an acid, by a metallic ion or ammonium ion
define acid salt
the salts formed by partial replacement of the replaceable hydrogen ion of an acid molecule by a basic radical
define normal salt
the salts formed by complete replacement of the replaceable hydrogen ion of an acid molecule by a basic radical
define basic salt
formed by partial replacement of hydroxyl radicals of a diacidic or triacidic base with an acid radical
general methods of preparation of salts
- direct combination
- displacement
- double decomposition
- neutralization of an insoluble base
- neutralization of an alkali (titration)
- action of dil. acid on carbonates/ bicarbonates
how to prepare insoluble salt from another insoluble salt
convert the insoluble salt reactant to soluble salt using dil. HNO3
then do double displacement and combine it with another soluble salt
why can’t H2SO4 be directly added to PbCO3 (insoluble) to make PbSO4
because PbSO4 is insoluble and forms a coating on PbCO3 , thereby the reaction slowly comes to a stop
define hydrolysis of salts
reaction in which salts react with water to form base (alkali) and an acid i.e. a solution which is acidic, alkaline, in nature
