acid base salts Flashcards
definition of acid
acid is a proton donor(H+),produces hydrogen ions when dissolved in water
why does HCl work in water but not methylbenzene
acid behaviour only takes place when hydrogen chloride dissolved in water,HCl is a covaalent substance,when dissolved in methylbenzene substance still contains hydrogen chloride molecules,in water hydrogen chloride molecules dissociate into hydrogen ions and chloride ions
what are the uses of acid
HCl:digest food in stomach,sulfuric acid:electrolyte in car batteries,carbonic acid:fizzy drinks,nitric acid:makes fertilizers and explosives,ethanoic acid:make vinegar and preservatives,Tartaric acid:used in fruit juice
organic acid definition and examples
Naturally occuring,weaker,less corrosive,citric acid(lemon),lactic acid(sour milk),malic acid(apple)
Mineral acid definition and examples
man made,stronger,more corrosive,sulfuric acid,nitric acid,hydrochloric acid,carbonic acid,sulfurous acid,phosphoric acid.
Physical properties of acid
sour taste,turns blue litmus red,universal indicator red,methyl orange-red,thymophthalein-colourtless,phenophtalein-colourless,they are electrolytes which conduct electricity because ions are produced in solution
Chemical properties
acid+metal=salt+hydrogen,acid+carbonate=salt+water,carbon dioxide,acid+base=salt+water(neutralisation,acid+metal oxide=salt +water,acid+metal hydroxide=salt+water.
Properties of strong acids
fully ionise in solution to produce ions,concentration of hydrogen ions are higher so more bubbles observed,good proton donor,strong electrolyte(good conductor of electricity)
properties of weak acids
partially ionised in solution,double arrow in equation,concentration of hydrogen ions lower,poor proton donor,weak electrolyte(bad conductor of electricity)
Strength and concentration of acid
strength(fully or partially ionise),concentration(amount of particles dissolved in a unit volume).
what is the basicity of acids
number of hydrogen atoms in an acid which can be replaceable by metal ion
Examples of monobasic,dibasic and tribasic acids
Monobasic:HCl,HNO3,Dibasic:H2SO4,H2CO3,Tribasic:H3PO4,reaction faster in dibasic than monobasic and etc.
Definition of base
proton acceptor
What is usually a base
metal oxide or metal hydroxide
What is an alkali
A soluble base that produces OH- in aqueous solution,it is a metal hydroxide
Example of common alkalis
sodium hydroxide solution,potassium hydroxide solution,calcium hydroxide solution(limewater)
4 Use of bases
sodium hydroxide:make soap,Potassium hydroxide:dye cloth,Calcium hydroxide:adjust acidic concentration of soil,Ammonia solution:Make fertiliser
Physical properties of alkali
Bitter taste,soapy feeling,turns red litmus paper blue
INdicators change in alkali Litmus,universal,methyl orange,thymolphtalein,phenophtalein
Litmus:blue,universal:blue,methyl orange:yellow,thymolphtalein:blue,phenophtalein:pink,all common alkalis are electrolytes
Chemical equations of bases
alkali+ammonium salt=salt+water+ammonia(with heating),alkali+acid=salt+water,Alkali+metal salts=metal hydroxides+salt (most metal hydroxides are insoluble in water so alkalis give precipitates with solutions of most metal salts
strong and weak alkalis
strong alkalis fully ionise in solution to produce ions,all alkaline molecules become ions in water,weak alkalis are partially ionised in solution,only few molecules react with water to form ions
Types of oxides
Acidic,basic,amphoteric,neutral
Definition of acidic oxides and examples
react with water to produce acids,usually oxides of non metals,sulfur trioxide,sulfur dioxide
Definition of basic oxides and examples
react with water to produce alkalis,usually oxides of metals.Potassium oxide,sodium oxide
Definition of amphoteric oxide and examples
behave as an acidic/basic oxide,react with acids/alkalis to produce salts,usually oxides of metals.Aluminum oxide,zinc oxide,lead(II)oxide
Definition of Neutral oxide and examples
insoluble in water,no reaction with acid/alkali,oxides of non metals.Carbon monoxide,nitrogen monoxide
pH definition
measure of strength of an acid or alkali
what is a pH scale
set of values ranging from 0 to 14.less than 7=acidic,7 is neutral,more than 7 is alkali
what happens as ph increases and decreases
conc of OH- ions increase as ph increase and conc of H+ions increase as ph decreases
indicators change colour in solution of differnt pH values.Methyl orange,litmus,phenophtalein
Methyl orange acidic:red pH4 colour change,Alkaline:yellow.Litmus Acidic:red pH 7 colour change,Alkaline:blue.Phenopthalein Acidic:colourless pH 9 colour change,Alkaline:pink
2 methods to determine pH of solution
Universal indicator and pH meter-electric meter more accurate than indicator.
Colour in universal indicator at different pH
1,2=red,3,4=orange,5,6 yellow,7=green,8,9,10=blue-green,11,12=blue,13,14=violet
why is soil pH controlled
if pH of soil is too low or high plants do not grow well,most plants require soil pH of 7-8 to grow.slaked lime or quick lime is added to increase pH of soil above pH7 which is called liming the soil
definition of a salt
substance formed when hydrogen of an acid is partially or completely replaced by a metal ion or an ammonium ion
Acids and their salts
acids with name ending with’ic’ will form salt ending in ‘ate’.acid with name ending with’ous’ will form salt with name ending in ite.
Difference of normal salt and acid salts
normal salt is one which all hydrogen ions are replaced.Acidic salts is one in which only some of hydrogen ions of dibasic or tribasic acid are replaced
what are hydrated salt
salts which contain water molecules inside their crystal structure essential for shape and colour,called water of crystallisation.number of water molecules present in salt is called degree of hydration.When heated salts lose water of crystallisation(lose shape and colour),salts without water of crystallisation called anhydrous salts
use of salts
medical,manufacture fertiliser,paint,photography
what to do with salt with high gradient in solubility curve and almost no change in solubility curve.
evaporate to dryness or cooling
preparation of salts for insoluble and soluble salt
insoluble salt=reactant used and other products formed must be soluble to obtain salt by filtration.soluble salt=reactant used and other products formed must be insoluble so salt can be obtained by filtration as filtrate
