ACIDS, BASES AND SALTS

BY JUDY

What are the properties of acids and bases

• Corrosive (burns your skin)• Sour taste (lemons, vinegar)• Contains hydrogen ions (H+) when dissolved in

water• Turns blue litmus paper to a red color • Reacts with bases to form salt and water• Reacts with metals to form from hydrogen gas• Reacts with carbonates to form carbon dioxide,

water and a salt.

How did Arrhenius define an acid and a base

• An Arrhenius acid is a substance that when added to water increases the concentration of H1+ ions present.

• An Arrhenius base is a substance that when added to water increases the concentration of OH1- ions present.

How did Lewis define an acid and a base

• A Lewis acid is defined to be any speices that accepts lone pair electrons . The H+ is a Lewis acid since it can accept a lone pair while OH- and NH3 are Lewis bases both of which donate a lone pair.

How are the hydrogen ion and the hydroxide ion related in

an aqueous solution • If you refer to the figure ions in solution electrolytes, you will see that

pure water does conduct some electrical current, albeit much less than-even the weak electrolytes.

• This is because water its self is a very weak electrolyte. • It ionizes to hydrogen ions and hydroxide ions to an extremely small

extent.

How is the hydrogen-ion concentration used to classify a solution as neutral, acidic, or basic

• When the pH is below 7 the solution is acidic.

• When the pH is 7 the solution is neutral

• When the Ph is above 7 the solution is basic.

What is the most important characteristic of an

acid-base indicator? *Such substance like phenolphthalein which is

colorless in an acid solution but becomes pink or red in a basic solution are called acid=base indicators.

*Chemical indicators are acid-base conjugate pairs whose acid form and base form are different colors.

*They are often employed for determination of the pH of solutions.

What are the products of the reaction of an acid

with a base? • When an acid and a base are placed

together they react to neutralize the acid and base properties, producing a salt.

What is the endpoint of a titration?

• Titration is a procedure used in chemistry in order to determine the morality of an acid or a base.

• A chemical reaction is set up between a known volume of a solution of unknown concentration and a known volume of a solution with a known concentration.

When is the solution of a salt acidic or basic?

• The bystander ions in an acid-base reaction form a salt solution.

• Most neutral salts consist of cautions and anions listed in the table on the right.

• These ions have little tendency to react with water.

• The salt consisting of these ions are neutral salts.

• For example: NaC1, KNO3, CaBr2,CsC1O4.

What are the components of a buffer?

• Water is determinant to interactions of biological in H+ and OH- ions the interfering with ions and charged bimolecular.

Web sites

• www.qldscienceteachers.tripod.com• www.facultyfp.sailsbury.edu/dfrieck/htdocs

/212/rev/acidbase/arrhenius.htm• www.nyu.edu/classes/tuckerman/honors.c

hem/lectures/lecture_21/node4.html• www.hyperphysics.com